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ESSAYS
-A N D
OBSERVATIONS,
PHYSICAL and LITERARY'.
Read before a Society in Edinburgh*
and publijhed by them .
Volume L
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E D I N B U R G im¬
printed by G. Hamilton and J. Balfoub3
Printers to the Univerlity.
M,DCC,LIV.
••
■v
' : 4 I
PREFACE.
AFTER the medical fociety of Edin¬
burgh had publiflhed thofe volumes of
Effays, which have met with fo favourable
a reception from the public, a propofal was
made them to enlarge their plan, and to car¬
ry their difquifitions into other parts of na¬
ture, befide fuch as more immediately relate
to the branches of medicine,, All the fci-
ences are remarked to have a clofe connexion
together ; but none more than thofe of me¬
dicine and natural philofophy : And the foci¬
ety foon obferved, that, fhould it turn its in¬
quiries into more general knowledge, it could
reap the advantage of preferving all its old
members, and needed but open its door to
Gentlemen of other profeffions, who might
enrich it with their obfervations and difco-
veries.
Soon after the fociety had received a new
form, feveral misfortunes happened, which
retarded its progrefs, and have hitherto pre¬
vented it from communicating any thing to
the
IVo
PREFACE.
the public. The rebellion broke out in this
country 5 and both fcattered the members
for fome time, and engaged their attention
to fubjedts, lefs agreeable and more intereft-
ing, than general difquifitions into nature.
No fooner were public affairs compofed, than
we met with an irreparable lofs in the death
of Mr. Maclaurin, one of our fecretaries.
The great talents of that Gentleman are ge¬
nerally known and highly efteemed in the li¬
terary world ; but the fociety have, aifo, par¬
ticular reafon to regrete in him the lofs of
thofe qualities, which form an excellent a-
cademician. Indefatigable himlelf, he was
a perpetual fpur to the induftry of others ;
and was highly pleafed with the promotion of
knowledge, from whatever hands it came.
At the time of his death, a number of dis¬
coveries, fufficient to have formed a volume,
had been communicated to him ; but, being
mingled with his other papers, have been
diffipated by various accidents 5 and the fo-
dety could recover but few of them.
T HE
PREFACE,
The objed of this fociety is the fame
with that of the other academies, which have
been eftablifhed in different parts of Europe ,
the promoting of natural philofophy , and of
literature , by communicating to the public
fuch differtations as {hall be tranfmitted to
them, either by their own members or by
others. "Tis allowed, that thefe two branches
of learning, efpecially the former, are more
promoted by the obfervation of fads than
by the mod ingenious reafonings and deputa¬
tions. To a diligent, and even fometimes to
a carelefs inquirer, many valuable experi¬
ments, no doubt, occur ; and thefe would
enrich our colledions, tho’ without this me¬
thod of conveyance, they would be intirely
loft to the public. The united judgments too
of men corred and confirm each other by
communication, their frequent intercourfe
excites emulation, and from the comnarifon
J i
of different phenomena, remarked by diffe¬
rent perfons, there often refult general truths*
of which, from one of thefe fhceno?nena , no
man of the greateft fagacity could entertain
any
P R E FA C E.
%
VI.
any fufpicion. Tho5 the collection of ex¬
periments feems continually, by means of
the learned focieties, and the labours of in¬
dividuals, to be augmenting, we need not
entertain any apprehenfions, that the world
will ever be overwhelmed by the number of
confufed and independent obfervations. The
heap does not always go on, increafing in
bulk and diforder, thro* every age. There
arife, from time to time, bold and happy ge-
niufes, who introduce method and fimplicity
into particular branches of fcience ; and re¬
ducing the fcattered experiments to more
general theorems, abridge the fcience of na¬
ture. Hints of this kind, we hope, may
be able to pafs thro" our hands ; and at worft,
our collections will be a fpecies of magazine,
in which faCts and obfervations, the foie
means of true induction, will be depofited for
the purpofes of philofophy.
The fciences of theology, morals, and
politics, the fociety are refolved intirely to
exclude from their plan. However difficult
the inferences in thefe fciences, the faCts, on
which
PREFACE.
Vile
which they are founded, are extremely obvi¬
ous ; and we could not hope, by our colledi-
ons, to be, in this relped, of any fervice to
the public. The great delicacy of the fub-
jed, the imperfedions of human under-
ftanding, the various attachments and incli¬
nations of mankind, will for ever propagate
difputes with regard to thefe parts of erudi¬
tion. And ’tis the peculiar happinefs of geo¬
metry and phyfics, that, as they intereft lefs
the paflions of men, they admit of more
calm difquifition and inquiry.
It is not that the fociety exped or pro-
pofe, that what they communicate will be
intirely above doubt or difputation. The pa¬
pers, indeed, which they print, were all
red before them, and they gave their confent
to the inferting them in their colledions: But
they pretend not to warrant the juftnefs of e-
very reafoning, nor the accuracy of every
obfervation. The author alone of each pa-
peris anfwerable for the contents of it : And
the fociety are as willing to infert what may
,)e communicated in oppolition to the fenti-
ments
vim PREFACE.
ments of any of its members, as in confir¬
mation of them.
The fociety are fenfible that it belongs a-
lorre to the public to decide concerning the
value of any invention $ and all the merit
to which they pretend, is that of exciting the
induftry of the learned, and of conveying
their productions to the notice of the world.
They affume not fuch authority as to itamp
their approbation on any performance, even
thofe which they communicate, much lefs
thofe which have barely been red before
them. If ever their teftimony has been cited
by any author in favour of his books, rea-
fonings, or machines, they hereby declare,
that this liberty has been ufed entirely with¬
out their confent or knowledge, and proceeded
alone from the fond opinion, which the wri¬
ter had entertained of his own performance.
Whoever will favour the fociety with any
difcourfe which it comprehends in its plan, may
fend their papers to either of the fecretaries,
Mr. Alexander monro Profefibr of Anato¬
my at Edinburgh , or Mr. David Hume
Library-keeper to the faculty of Advocates,
CONTENTS.
Art. Pag.
I. QP the Laws of Motion ; by the Honour¬
able Henry Home, Efquire , one of
the Senators of the College of JitJlice . i
II. Some Remarks on the Laws of Motion , and
the Inertia of Matter ; by John Stewart,
M. D. Fellow of the Royal College of Phy -
ficians , Prof e for oj Natural Philofo -
phy in the Univerfty of Edinburgh. 70
III. Pappi Alexandria! colleclionum mathema¬
tic arum libri quarti propoftio quart a genera-
lior fadla , cui propoftiones aliquot eodem
fpedl antes adjiciuntur\ auBore Mattheo
Stewart, in Academia Edinenf Mathe-
feos Profejfore. 14 1
IV. Of the Caufe of the Variation of the 0-
bliquity of the Ecliptic , by Colin Mc-
Laurin, late Fellow of the Royal Society ,
and Profeffor of Mathematics in the Uni -
verfuy of Edinburgh. 173
V. Concernhig the Judder and furprifing Chan¬
ges objerved in the Surface of Jupiter's Bo¬
dy 1 by the fame. 184
Art.
CONTENTS.
a
Art. Pag*
VI. Obfervations on 'Thunder and Electricity ,
by Ebenezer Mcfaxt, M. D. 189
VII. Some Phaenomena obfervable in foggy
Weather ; by the fame. 197
VIII. Of the Meajures of Scotland, compa¬
red with thofe of England, by James
Gray. 200
IX. A Dijfertation on the Sexes of Plants ;
by Charles Alston, M. D. King s Bo -
tanjft in Scotland, Fellow of the Royal
College of Phyfcians , and Profeffor of Me¬
dicine and Botany in the Univerfty of E~
dinburgh. 20 if
X. Remarks on chemical Solutions and Preci¬
pitations 5 by Andrew Plummer, M.D*
Fellow of the Royal College of Phyficians,
and Profeffor of Medicine and Chemifry
in the Univerfty of Edinburgh. 284
XL Experiments on Neutral Salts , compound¬
ed of different acid Liquors , and alcaline
Salts , fixt and volatile ; by the fame, 315
XII. Experiments and Obfervations upon the
Hartfell Spaw, made at Moffat 1750 ;
and an Account of its Medicinal Virtues ,
fo far as they have hitherto been difccvered
from
CONTENTS.
in
Art. Pag.
from Experience ; by William Horse-
burgh, M. D. 341
XIII. Of the various Strength of different
Lime-waters , by Robert Whytt, M.D.
F. R. S. Fellow of the Royal College of
Phyjicians , and Profeffor of Medicine in
the Univerfity of Edinburgh. 372
XIV. Of the anthelmintic Virtues cf the Root
of the Indian Pink, being Part cf a Let¬
ter from Dr . John Lining, Phyfician at
Charleflown in South Carolina, to Dr .
Robert Wiiytt, Profeffor of Medicine
in the Univerfity of Edinburgh. 386
XV. The Hi/lory of a Cure performed by
large Dofes of an alterative mercurial
Medicine , communicated to Dr, Plum¬
mer ; by Mr, George Dennistoun,
Surgeon in Falkirk.
390
XVI. A Dejcription of the feminal Veffels ,
by Alexander Monro, Student cf Me¬
dicine in the Univerfty of Edinburgh . 396
XVII. The Df TeBion of a Woman with child ,
and Remarks on gravid uteri ; by Dr. Do¬
nald Monro, Phyfician at London. 403
XVIII. Additional Obfervations on gravid
uteri, by Alexander Monro, Student
IV
CONTENTS.
Art. Pago
of Medicine in the Univerfty of Edin¬
burgh. 426
XIX. Of the Difference between Refpiration
and the Motion of the Hearty in feeping
and waking Perfons ; by Robert Whytt,
M. D. &c 436
XX. Remarks on the Inter cofal Mufcles ; by
Alexander Monro, F. R. S. Pro -
feffor of Anatomy in the Univerfty of E-
d Inburgh. 447
XXL Pke Cure of a fractured Tendo Achil¬
las ; by the fame. 430
XXII. An Account of the Dijeafe called Mill-
Reek by the Miners at Leadhills, in a Let¬
ter from Mr. James Wilson, Surgeon
at Durrifdeer, to Alexander Monro,
P, A. 459
ESSAYS
ESSAYS
AND
Hi l
OBSERVATIONS
♦ 4
PHYSICAL and LITERARY.
Article I.
Of the Laws of Motion ; by the Honourable
Henry Home, Ej quire , one of the Senators
of the College of Jiftice.
NO thing has more perplexed philo-
fophy, than an unlucky propenfity,
which makes us grafp at principles,
without due regard to facts and experiments,
Tho’ fond of knowledge, we are willing to
purchafe it at the eafieft rate ; and general
principles delight us, becaufe they fhorten
the read to knowledge- This bent of the
mind is productive of manifold errors. Pre-
pofleffed once by a favourite principle, we are
no longer open to conviction. Every phe-
A nomenoi*
2 Essays and observations
nomenon mull be accommodated to that
principle, and every oppofite fad:, however
obftinate, inuft go for nothing. And thus
we endeavour to mould nature to our wifh,
inftead of defiring to know nature in her ge¬
nuine figure. •
We fee, then, that in fcience, as well as in
adlion, appetite and inclination generally gain
the afcendant. Even in natural philofophy,
theory was introduced before experiment,
and every philofopher urged his own notions,
without regard to truth or reality. This
produced a mafs of undigeited and contradi¬
ctory theory 5 which at length could not fail
to bring on the difcovery, that the whole was
little better than fancy and chimera. The
difcovery had a remarkable good effed; ;
which was, firft to make us doubt of every
thing, and then to make us fearch after
truth in the more painful road of induction.
By this means, a greater number of im¬
portant truths have been brought to light
within a century or two; than before that
time from the beginning of the world.
But tho’ our only fore guides to truth are
fads and experiments, it is however expedi¬
ent to keep the end in view. Fads and ex¬
periments
PHYSICAL and LITERARY. 3
periments are ufelefs lumber, if we are not
to reafon about them, nor draw any confe-
quences from them. In all our operations, we
may have an eye to theory : nay we muft have
it ; for fuch is the conftitution of our mind.
Theory becomes only a fource of error, when
we indulge in it too much, or attach ourfelves
to it beyond what fadts and experiments can
juftify. In fhort, theory is vain without ex¬
periments, and experiments are beft under-
flood by applying them to theory.
Natural philofophy, it muft be acknow¬
ledged, is far from being ripe for firm and
lafting theory. But we have fadts and expe¬
riments in great abundance, to be a founda¬
tion for theoretical {ketches ; which may be
fafely indulged, provided they be done in fo
flight a manner, as to leave the mind free
from any wrong bias. Tho1 we have not ma¬
terials for a regular building, there is nothing
to hinder us to venture upon a model.
Almost every author who treats of the
laws of motion, has thought it incumbent up¬
on him to fet out with a definition of motion.
And, in a thing fo Ample, it may appear
ftrange to find fuch a variety of definitions :
whence one thing may be gathered, that none
4 ESSAYS and OBSERVATIONS
of thofe definitions have been approved of by
fucceeding authors. Epicurus defines motion
to be tc a paflage from one place to another : ”
and he might as well have defined it to be
S O
motion from one place to another ; becaufe
pafTage in this fentence means nothing diiter-
ent from motion. Sturmeus defines motion
to be £t fuccejjiva rei motcz in diverfis locis ex-
u iftentia f which is juftly blamed by Leib¬
nitz as defcribing the effedt of motion, rather
than the formal nature of it. And yet Leib -
nitz s own definition, cc Motus eft continua loci
mutatioP is not more fatisfadtory. But, of
all definitions that ever were attempted, Art-
jlotles definition of motion is the rnoft unin¬
telligible, cc Ac! us entis in potentra quateniis in
-cc potential which Locke condemns as abfolute
jargon ; and which, he fays, would puzzle
any rational man, to whom it was not already
known by its famous abfurdity, to guefs what
word it could ever be fuppofed to be the ex¬
plication of.*
But it is no wonder thefe authors have
not given fatisfadtion to each other, or to
their readers, upon this fubject ; for they
have attempted what is utterly impoffible,
viz.
f Locke concerning human undemanding, B. 3. ch. 4. §8.
PHYSICAL and LITERARY 5
* •
viz. to give a definition of a fimple idea.
They might as well have attempted a defini¬
tion of colour or found, of pain or any other
fimple feeling. It is to be regreted, that na¬
tural philofophers and mathematicians are
not always well {killed in logics, and of this
truth we {hall have but too often occaiion to
give examples.
Scarce any author that I know has
thought of giving a definition of reft; yet it is
not a more fimple objedl than motion. I can
guefs at the reafon, that reft is the more fa¬
miliar objedt; a greater number of things
appearing to be in a qmefcent ftate than in
motion. If every thing about us appeared
to move, we fhould be furprifed the firft
time we faw a body at reft, and probably
would endeavour to explain the thing to o-
thers : but both are equally incapable of a
definition. They are fimple objedls of fight
and perhaps of touch. Deprive us of thefe
two fenfcs, and W'e could never have the
leaft notion either of reft or motion.
When a being moves itfelf or moves, we
conceive the being as adting ; and in this
view motion is a fpecies of addon. But,
when a body is moved by being adted upon,
we
6 ESSAYS and OBSERVATIONS.
we conceive the motion of the body as an
effect produced by a proper caufe. In this
cafe the body does not adt, but is adted up¬
on. This, tho’ an evident diftindtion, does
not exclude felft motion from being alfo con-
fidered as an effect in a certain light, viz*
an effedt produced by a being upon itfelf.
Every thing which moves, and is not
barely moved or adted upon, rnuft be endu¬
ed with a power of motion. For this power
is involved in the very conception of felf-
motion. And the term power may be equal¬
ly applied to animate and inanimate beings,
fuppofing them to be equally felf-movers.
Wh ether matter in any cafe be endued
with a power of motion, is a celebrated
queftion, which is generally refolved in the
negative : and, as this queftion cannot be o-
verlooked in the prefent fpeculation, I fhall
endeavour to examine it with all the accu¬
racy poflible.
Matter is generally reprefented as alto*
gether unadtive and inert ; and indeed in a
fuperficial view the fad appears to be fo.
The bulk of the things about us feem to
be at reft, and we lay our account that they
will continue in that ftate, unlefs adted upon
PHYSICAL and LITERARY 7
by fome external force. If we lock up any
moveable object, we truft to find it in the fame
place ; and, if it be miffing, we afcribe
our lofs to thieves, not to felf- motion in the
body. Matter, fo far as we can difcover, is
certainly not endued with thought or volun¬
tary motion; and yet, that it is endued with a
power of motion in certain circumftances,
appears to me an extreme clear point. Drop¬
ping a ftone from a high tower, it falls to
the ground without any external impulfe, fo
far as we can difcover. Plere is an effedt
produced, which every one, who has not flu-
died philofophy, will attribute to a power in
the ftone itfelf. One would not hefitate to
draw .this conclufion, ftiould the ftone move
upwards ; and yet, fetting afide habit and
cuftom, it muft be evident, that a ftone can
as little move downwards as upwards with¬
out a vis motrix . And that this is a juft, as
well as natural way of thinking, will appear
by analogy. When a man is in motion, we
readily afcribe the effedt produced to a power,
which he poflfefles, to move his limbs. Why
then do philofophers deny to the ftone, in the
adf of falling, the power of beginning motion,
a power which they fo readily afcribe to the
man ?
8
ESSAYS anp OBSERVATIONS*
man ? If it be objected that man is a being
endued with a power of moving himfelf,
and of moving other things, the plain an-
fwer is, that thefe are fadts which we learn
no other way than by experience ; and we
have the fame experience for a voucher, that
a Hone fet free in the air will move itfelf.
And if it be farther urged, that man is a
thinking being, the anfwer will readily oc¬
cur, that a power of beginning yifible mo-*
lion is no more connected with a power of
thinking, than it is with .any other property
of matter or fpirit. Nay, Mr Loch holds,
that matter may be endued with a power of
thinking ; and, fuppoiing this power fuper-
added to the other properties of matter, it
cannot be maintained, that matter would be
rendered thereby more or lefs capable of be¬
ginning or continuing vifible motion.
But this is not the only inftance in which we
difcover an agency or adlive power in matter.
A billiard ball ftruck upon the ground, re¬
bounds with a confiderable force. A bow bent
by the hand, reftores itfelf with violence when
the firing is let go. In both, there is an inftant*
of reft betwixt the oppofite diredlions of the
motion. The ball rebounds, and the bow
reftores
PHYSICAL and LITERARY.
feftores itfelf to its former fhape, without
any external force, by an inherent power
which is known by the name of elafticity.
But we need not dwell upon particular in*
Ranees. Chemiftry dife overs various powers
in matter of the moft: aftive kind; and every
man who is converfant with the operations of
chemiftry, mud have a ftrong impreffion
that matter is extremely active.
For the fake of iiluftration, let us fup-
pofe a fubftance or thing having the follow¬
ing properties, that it makes no ref ftance to
bodies impinging upon it; that when carried
alone; in a man’s hand, even with the moil
violent motion, it does not increafe the mo~
mentum of the hand, and that it flops fhort
the inftant the hand ceafes to move. This
would certainly be the mod inert of all con¬
ceivable things. And if fo, matter cannot
he abfolutely inert or paffive, when its pro¬
perties differ fo widely from thefe deferibed.
In many circumftances matter begins motion,
and acts often with great violence. It has a
conftant endeavour, when once fet in mo¬
tion, to preferve itfelf in the fame degree of
motion, and, when at reft, is not put in
motion without refiftance*
B But
10
ESSAYS and OBSERVATIONS
But it is maintained by the bulk of our
philofophers, that matter is altogether inca¬
pable of aft ive powers ; that aftivity is con¬
fined to immaterial fubftances, and that in-
ertnefs is implied in the very conception of
matter. This moves them to afcribe to fome
invifible agency, all that aftivity which we
difcover in matter. In every one of the a-
bove inflances, matter, they fay, does not aft,
but is afted upon by the deity, who interpo-
fes by general laws, to prefer ve the unifor¬
mity of nature. Thus, when a ftone falls,
it is not the (tone which afts, but the deity.
It is the continual action of the deity -which
keeps the planets in elliptical orbits: and,
when a plague infefts the world, it is the de¬
ity who fpreads the infection, and directs
inert matter to ravage and deftroy. Arfenic
is not of itfelf a poiion ; it is the immediate
finger of God which makes it fo.
With regard to this whim fi cal doftrine,
which declares war againft our fenfes, it may
be observed, that natural philofophy is not
mucli artefted by it, of whatever errors it may
be productive in the more abftraft fciences.
For it is admitted, that the deity, in afting
upon matter, fubjefts himfelf to the fame
ft rift
PHYSICAL and LITERARY, u
ftridt and invariable laws which govern mat¬
ter, fuppofing it to have a power of motion.
Therefore, the hifiory of nature will be the
fame, upon either fuppofition. At the fame
time, as this hypothecs not only contradicts
common fenfe, but, in place of a beautiful
chain of caufes and effedts, difcoverabie in
the operations of matter, prefents a deform¬
ed and crude fcene, which detradts from the
wifdom of the deity 5 I think it of confe-
quence to bellow fome thoughts upon it: and,
I am hopeful to make it evident, that this
hypothecs is no better fupported by reafon
than by experience.
To put an end to a good deal of loofe rea-
foning upon this fubjedl, it will be neceffary
to aicertain the meaning of the terms mate¬
rial and immaterial ; which, fo far as I know,
has not been done with fufficient accuracy.
All beings and exigences mud be either ma¬
terial or immaterial ; or, in other words,
muft be matter or not matter : therefore, if
we know what is matter, we cannot be at a
lots about what is not matter. I take it for
granted, that we have no conception of mat¬
ter but as fubftance or body, endued with co¬
lour, figure, extenfion, impenetrability, or
other
j 2 ESSAYS AND OBSERVATIONS.
other properties of fuch a nature as to be ob«
jeds of our external fenfes. The dired op-
polite, muft of courfe be an accurate defer i-
ption of an immaterial fubftance, viz. that
which has properties of fuch a nature, as not
to lie open to any of our external fenfes,
more than colour to one born without fight.
Th us it comes out, that immateriality is
merely a negative term, comprehending eve¬
ry thing that is not matter. And it is of con-
fequence to be obferved, that the diftindion
betwixt material and immaterial, not being
founded on the nature of the things which
are fo diftinguifhed, but on the limited na¬
ture of our external fenfes, has not the lead
tendency to explain the nature or properties
of immaterial fubftances, further than bare¬
ly, that thefe properties are of fuch a kind,
as not to be the objeds of any external fenfe.
From thefe premifes, the following rea-
foning will, it is hoped, be found entirely
conclufive. Size, figure, motion, weight,
&c. are qualities of matter which are percei¬
ved by pur external ienfes : but there is none
fo foolith to maintain, that matter can have
no qualities but what are objeds of an external
Ccnlc, It would be the lame as to deny the
exigence
PHYSICAL and LITERARY 13
ex’ftence of immaterial fubftances becaufe
thefe do not exhibit themfeives to our fenfes.
Power is a property or quality, of which
none of our external fences afford us the per¬
ception; and therefore our want of percepti¬
on of power, does not more conclude a nega¬
tion of power to matter, than to fpirit.- In
general, we have no means to come at the
knowledge of a caufe, but by the effeB pro¬
duced. We cannot, a priori , conclude*
that animate beings are endued with any fort
of powers, more than inanimate. Experience
is here our only guide. We find by experi¬
ence man to be a reafoning being, endued
with many powers and faculties: and, by the
fame experience, we find matter to be endu¬
ed with certain powers and faculties. Both
are difcovered by the effects produced ; and
we have no other means to make a difcovery.
We fee a Rone fall without any external im-
pulfe. From that effect we have a juft foun¬
dation to conclude, that the ftone has a pow¬
er of moving itfelf. And, if we have not a
juft foundation to make this conclufion, we
have not a juft foundation to make this other
conclufion, that a man has a power of felf-
motion when we fee him walking. And af¬
ter
i4 ESSAYS and OBSERVATIONS.
after all, it mud appear extremely whimfi-
cal to deny to matter a power of motion,
merely becaufe matter difcovers itfelf to our
external fenfes in part ; when, at the fame
time, we are fo ready to attribute powers of
every fort to immaterial fubftances, which
cannot be reached by our external fenfes, ei¬
ther in whole or in part.
It is fuggefted above, that to endue mat¬
ter with a power of adling according to ge¬
neral and invariable laws, exhibits a more
beautiful and compleat fyftem, than to leave
it abfolutely inert, to require a continued in-
terpofition of the deity. To illuflrate this
point, I chafe to borrow the honourable Mr.
Boyle s fentiment, whofe piety was not infe¬
rior to his knowledge. £C It feems manifeft
cc enough, that whatfoever is done in the
6S world, at leaft where the rational foul in-
tervenes not, is really effected by corporeal
<c caufes and agents, according to the laws
££ fettled by the omnifcient author of things.’7
^ And he obferves, cc That as it more recom-
mends the (kill of an engineer to contrive
C£ an elaborate engine, fo as that there need
f inquiry into the vulgar notion of nature, p. 60.
PHYSICAL and LITERARY 15
Ce nothing to reach his ends in it, but the
cc contrivance of parts void of underftand-
cc ing ; than if it were neceffary that, ever
cc and anon, a difcreet fervant fhould be em-
c< ployed to concur not ably to the operations
“ of this or that part, or to hinder the en-
“ gine from being out of order : fo, it more
<c fets off the wild cm of God, in the fabric
cc of the univerfe, that he can make fo vafta
<c machine perform all thofe many things
<c which he defigned it fhould, by the mere
<c contrivance of brute- matter, managed by
€C ce tain laws of motion, and upheld by his
<c ordinary and general concourfe; than if he
C£ employed, from time to time, an intern¬
ee gent overfeer to regulate and controul the
<c motion of the parts fo'’ What maybe the
ooinion of others, I cannot fay; but, to me,
this argument is perfectly conclufive. Con-
fidering this univerfe as a great machine, the
workmanfhip of an intelligent caufe ; 1 can¬
not avoid thinking it is the more compleat,
the lefs mending or interpolation it requires.
The perfection of every piece of workman¬
fhip, human and divine, confifts in its an-
fwering
* Inquiry into the vulgar notion of nature. . p, 7.
i6 ESSAYS and OBSERVATIONS
fwering the defigned purpofe, without be-
flowing further labour upon it. And there¬
fore, upon the whole, as we have no foun¬
dation, either in reafon or experience, to de¬
ny activity to matter; I conclude, that the
doCtrine of the abfolute inertnefs of matter,
is not only repugnant to truth, but tends, in
an indirect manner, to arraign the deity of
want of power or of wifdom, or of both.
Of the VIS I N S I T A or VIS
E R T I JE
AVING thus brought our fubieCt with¬
in bounds, by evincing that we have
no occahon to fearch for any other im¬
mediate caufe of natural appearances than the
activity of matter itfelf; I fhail proceed to ex¬
amine fome of the powers of matter, fuch of
them as are productive of the moft remarkable
effeCts: and (hall begin wuth the vis injita , or
vis inertiae , that fignal property of matter,
whereby, as philofophers teach, £C A body
always
PHYSICAL and LITERARY. 17
cc always perfeveres in its Rate of reft, or of
cc uniform motion, in a right line, 'till, by
cc fome external influence, it be made to
cc change its Rate.” This property is han¬
dled by writers without any degree of accu¬
racy. The bulk of them refolve it into the
inertnefs and paffive nature of matter ; and
confider the prefent Rate of a piece of mat¬
ter, whether of motion or of reR, to be an
effedt, which, once produced, muR conti¬
nue to exiR as it is, Rill it be changed or de-
Rroyed by the operation of a new caufe. But,
as this conception of the matter is liable to
Rrong objections, which fliall by and by be
mentioned, the moR rational waiters admit
of a power in matter to prefer ve itfelf in its
prefent Rate ; but then, confidering the per-
feverence in reR and in motion, to be effedts
of the fame kind, they, without making a-
ny diRindtion, attribute both to the fame
pow7er or caufe.
I cannot fubfcribe to either of thefe noti¬
ons. It is obvious to me, that the mere ne¬
gation of a caufe, tho’ it may account for the
continuance of a body at reR, as it may ac¬
count for its prefer ving the fame figure or
colour 5 yet can never account for the re-
C fifiance
1 8 ESSAYS and OBSERVATIONS
fiance made in the change from reft to mo¬
tion, or from motion to reft. And it is e-
qually obvious, that a ftate of motion is very
different from a ftate of reft ; and that the
preferving a body in motion, muft be an o-
peration of a different kind, from that of
preferving it at reft.
In order to handle this fubjedt with fome
degree of accuracy, I fhall endeavour to make
out the three following propositions:
That motion is a continued addon, which
muft infer fome power continually adding.
Secondly , That as matter refifts a change from
reft to motion, as well as from motion to reft,
this refiftance is not to be accounted for by
the mere negation of a caufe, but is a poft-
tive effedl to require a caufe as much as mo¬
tion does. And, lajlly , after explaining the
caufe of the continuance of motion, I fhall
endeavour to fhow, that it is an effedt of a
y
different kind from the refiftance which mat¬
ter exerts againft any impuife which puts it
in motion.
With regard to the flrft proposition, mo¬
tion evidently differs from the other proper¬
ties of matter. It is not like extenfion, fi¬
gure, and fuch like qualities effential to mat¬
ter.
PHYSICAL and LITERARY. 19
ter. Every body mu ft be of a certain fize
and figure ; but it is eafv to feparate motion
from body, by fuppofing it to be at reft.
But what we have principally to confider in
the prefent argument is, that the moulding
of a body into a certain figure, or the giving
it a certain colour, are not imperfedt, but
compleated effedts ; which, once produced,
muft continue invariably the fame, until fome
power be exerted to make an alteration. This
is involved in the very conception of colour
and figure, and is fo Ample and clear a pro¬
position, as to be incapable of any illuftrati—
on. The bare negation of a new caufe, is
fufficient to account for the continuance of
fuch effects. Reft is of the fame kind. It
requires no adtion or operation to prefer ve a
body at reft, more than to preferve its colour
or figure. But motion, being the diredt op-
pofite of reft, cannot be one of thofe corn-
pleat effedts, which, once produced, muft
continue invariably the fame. Motion, by
the very conception of it, is action. While
a body is in motion, it is in continual adtion;
and, as adtion implies power, there muft be
a power continually exerted to preferve a bo¬
dy in motion. Again, if motion be con fi¬
de red
20 ESSAYS AND OBSERVATIONS
dered as an effed, it can only be compared
to figure or colour, with regard to that part
of it which is paft : what part remains to be
performed, is fo far from a compleated effed:,
that it is not fo much as commenced ; and
%
therefore muft neceffarily be conceived as a
different e fifed, to the produdion of which
there muft be a new exertion of power.
Motion then is a continued effed, or rather
a feries of different effeds, to require a caufe
in continued adion. Accordingly, when
we attend to our own perceptions, we do not
inquire for a caufe, when a body ceafes to
move. If the caufe of the motion ceafe,
we feek no other reafon for the ceafing of
the motion. If a thing fo evident can ad¬
mit of illuftration, let us figure an animal in
motion. It never came into the mind of a~
ny perfon, that a man is paffive in the adion
of walking or running. In this cafe we rea¬
fon juftly, that walking or running requires
a continued exertion of power. It requires
no exertion of power to put an end to thefe
motions. The man has but to forbear to ex¬
ert his power, and reft enfues. In this mat¬
ter there is no difference betwixt animate and
inanimate beings ; not even tho’ it fhouid be
fuppofed
PHYSICAL and LITERARY. 21
fuppofed, that matter is altogether paffive.
For, if matter itfelf has not a power of mo¬
tion, the fpirit which actuates matter, cannot
other ways prefer ve it in motion, but by a
continued exertion of potoer,
The fecond proposition is almoft felL
evident. To account for continuance at reft,
nothing is required except barely the nega¬
tion of a caufe. But matter at reft not only
continues in that ftate, but plainly refills e-
very force which tends to change its ftate
from reft to motion. Matter makes no re-
fiftance to any caufe which produces an alte¬
ration in its figure or colour. Refiftance is a
pofitive effedl which requires a pofitive caufe.
And this property of refiftance which all mat¬
ter is endued with, is a principle diredtly op-
pofite to inertnefs or pafieity, if I may ufe
that term. Refiftance is plainly aftion, which
every man may readily perceive in himfelf,
when an impulfe is made upon him : and,
were matter abfolutely paffive and inert, it
would make no refiftance, but be carried on
by every impulfe, without diminifhing the
force of the impelling body.
W ith regard to the third propofition, we
cannot be at any lofs to affign a caufe for the
continuance
22 ESSAYS AND OBSERVATIONS,
continuance of that quantity of motion which
is once given to a body. If the intervention
of fpirit be rejedted as above, there is but an¬
other hypothefis to recur to, which is, That
inanimate matter is endued with a power to
preferve itfelf in motion, as well as animated
matter is, without any other difference, but
that the former having no will or feeling, adts
blindly and invariably by an eftablifhed iaw«
It has no fpontaneous motion, becaufe it has
no will. Neither has it in every circumftance
a power of beginning motion ; but, when
once fet in motion, it has a power given it by
the Author of nature to continue itfelf in mo¬
tion. And this is a law which regards all
matter without exception.
And this power being once eftablifhed, it
remains only to be made out, that it is of a
different kind from that which refills a change
from reft to motion, and from any degree of
motion to a greater. The thing is obvious ;
for, as caufes are beft diftinguifhed by their
effedts, the caufe cannot be the fame of two
effects diametrically oppofite, viz. preferving
a body in motion, and oppofing motion. It
may ferve to clear this matter, if we attend
to the diftinction betwixt impulfe and refin¬
ance*
I
PHYSICAL and LITERARY.
23
\
ance. They are Ample ideas, and therefore
incapable of a definition 5 but their difference
will be obvious, by confidering a man in the
aft of pushing againft an obftacle, and bare¬
ly refifting force applied againft him, without
pushing again, or counterafting. The man,
no doubt, is aftive in refifting, as well as in
pushing y but the aftions are very different in
their nature, and carefully to be diftinguiftied
in accurate reafoning. In a word, the ten-
dency of impulfe is, to produce motion ; the
tendency of refiftance is, to prevent it. Thefe
powers, therefore, fo oppofite to each other,
fhall hereafter be diftinguiftied by different
names. The vis injiia final 1 be appropriated
to that power which is favourable to motion ;
leaving the other power which refills motion
to be denominated by the vis inertia?, or ra¬
ther vis reji ft entire.
Tho’ this vis inertia be a power, as obfer-
ved, inherent in all matter, there are certain
experiments which may appear to clafh with
it, and which, upon that account, merit at¬
tention. If a round ball be laid upon a ho¬
rizontal table in vacuo , in which fituation
there will be no counteraftion of gravity, it is
certain, that the fmoother the ball and table
are.
£4 ESSAYS and OBSERVATIONS
are, the refiftance will be the lefs : and they
may be made fmoother and fmoother, till the
refiftance be quite infenfible. If the refift¬
ance do not vanifti altogether, it may be ow¬
ing to our want of art to make any furface
abfolutely fmooth. There is no reafon, it
may be thought, to afcribe the fmall remain¬
ing refiftance to a fuppofed vis inertia^ when
it can be accounted for by other caufes > and
that it is unphilofophicai to fuppofe the exift-
ence of a caufe, when we cannot point out a
tingle effedt that refults from it, and from no
other caufe.
But there is another experiment of the
very eafteft operation, and which is liable to
no ambiguity. Let a body of any determined
weight be fufpended by a thread or rope fix’d
to a hook in the ceiling : the leaft conceive-
able force will put this body in motion. If
any refiftance at all be felt, it ought to be at¬
tributed to the denfity of the air, not to the
body. And indeed thefe experiments infer,
no more than what is admitted by every phi-
lofopher, that the fmalleft force is fufficient
to move the greateft body. It is acknowled¬
ged, that, were the globe of the earth fuf¬
pended by a chain, there is not a force fo>
fmall.
PHYSICAL and LITERAL Y. 2§
finall which it would not yield to. Thefe* ■
and Rich like experiments, look as if matter
had no attachment to reft, no vis rejijlentice ,
but that it readily yielded to motion. That a
body is put in motion by the very fmalieft
force, and yet that it refills a change from
reft to motion, are propofitions which may
appear not to be very confident : yet both
are true in fact. And the difficulty will va-
nifh, by attending to the power of the vis
inertiae or refiftentiae , that it is not meafured
merely by the fize or bulk of the body to
which it belongs, but has a relation to the
j momentum of the impingeing body. The leaft
force will put the greateft body in motion 2
but from this it doe§ not follow, that matter
does not refift a change from reft to motion.
It only follows, that this refiftance is always
lefs than the vis matrix . To calculate the
proportion betwixt the vis matrix and the re¬
fiftance of a body at reft, (hall be the (abject
of the next chapter.
D
Of
26 ESSAYS AND OBSERVATIONS
Of the COMMUNICATION
of MOTION.
H E Communication of motion from
r
A one body to another, has been ex¬
tremely puzling to metaphyficians ; tho’ not
to practical philofophers, who make no dif¬
ficulty to fuppofe, that motion actually paffes
out of one piece of matter into another. Let
us figure one billiard ball at reft, and ano¬
ther dire&ed upon it with a certain velocity ,
It is under ftood that part of the motion of
the impingeing ball paffes into that which is
at reft, after which it proceeds to move with
that degree of velocity which is communi¬
cated to it. This account of the matter ap¬
pears to me altogether abfurd. Motion can¬
not iubfift by i tie If to be' transferred from
place to place, or from body to body. It is
one of the qualities or properties of matter ;
and it is; no lefs repugnant to the very conce¬
ption oi the thing, that the motion of one
PHYSICAL and LITERARY.
body can pafs from it to another, than that
the figure of one body can pafs from it to an¬
other. In general, qualities, properties, and
affedfrons, are infeparable from the particu¬
lar bodies to which they belong. They have
no feparate exiflence, and therefore cannot
be conveyed, even in the imagination, from
one body to another. The green colour of
this field, cannot be taken from it, and be¬
llowed upon another. All that can be done.
Is to give the other a fimilar colour. My i-
deas or feelings cannot be conveyed from me
to any other perfon, tho’ fimilar feelings
or ideas may be produced in that other per¬
fon. This is not a play about words; it leads
to the explanation of a phoenomenon which
natural philofophers have not been able to ex¬
plain with any fatisfadlion. When motion is
produced in one body by the impuife of an¬
other, there is no neceffity to embrace fa ab-
furd a dodlrine, as that motion pafies from
the one to the other. The motion produced
is eafily deducible, from the principles above
laid down. The vis injit a and the vis reji -
flentiae , are fufficient to account for all the
effe<fts that proceed from the collifion of hard
bodies which have no elailicity. If the re-
fiflance
28 ESSAYS AND OBSERVATIONS
fiftance of a body is always lefs than the im-
preffed force, the refitting body, after its re-
fiftance is overcome, muft neceftarily be car¬
ried along with the body which impinges up¬
on it. And, being once put in motion, its
oven vis injita preferves it in the fame degree
of motion. I am here putting the fimpleft
cafe, that of a body in motion, impingeing
upon one at reft $ and, for the eafe of the i-
magination, I fhall fuppofe thefe two bodies
equal. In this cafe it is afeertained by expe¬
riments, that the two bodies in contabl, go
on with half the celerity which the impinge¬
ing body had before the collifion. For it is
a general rule in the percuffion of hard bo¬
dies, that the momentum or force, dire died to
the fame point, continues the fame after con¬
tact as before. There is no difficulty here :
for after half of the force of the impingeing
body is deftroyed, by the refiftance of the
body at reft; the other half remains, with
which the impingeing body moves, and car¬
ries along with it. the other body from reft to
motion. When the refiftance of the body
at reft is once deftroyed, it yields to the im-
preiied force without any further oppofition;
and
PHYSICAL and LITERARY.
29
and, by its impenetrability, muft be carried
along with the other.
But, in order to form an accurate notion
of this operation of percuflion, two prelimi¬
nary points muft be fettled. The firft is, to
determine the precife nature of the aCtion ex¬
erted by a body at reft when impelled by one
in motion. Does the body at reft return
ftroke for ftroke, or impulfe for impulfe ?
Does it truly read, or does it barely refill ?
That it refills only, and does not read, will
be evident from a fingle confideration, which
is, that motion is effential to impulfe, not at
all to refiftance. Now, if the body at reft
readts, by returning ftroke for ftroke; it muft
rufh upon the impingeing body, and carry it
backwards at lead for feme final 1 fpace :
which cannot be ; becaufe, once admitting a
retrograde motion, the vires inf it re of the two
bodies muft carrv them on in the fame dire-
j
ction, which is contrary to fact. It is obvi¬
ous, then, that there can be no repercufiion
or reaction of the body at reft. All the ob-
ftrudtion it gives to the action of the impinge¬
ing body, muft be merely by refiftance. The
other point to be fettled is, whether the ope¬
ration be inftantaneous, or whether it be per-
forpre$
ESSAYS and OBSERVATIONS
3°
formed in time ? That it is inftantaneous,
will thus appear. A gradual change of mo¬
tion fuppofes, that the foremoil: body paffes
through every degree velocity from reft, till
it acquires its greateft velocity ; and that the
motion of the impingeing body is gradually
retarded in proportion. But this iuppofition
is inconiiftent with a known faft, that the bo¬
dies continue conjoined after contadt $ whence
it is evident, that both muft move with the
fame velocity from the inftant ofcontadL
These preliminary points being fettled, the
operation may be eafily analyzed. Tho’ the
whole is performed in an inftant, it may,
however, be diftinguitlied into different fteps.
The fir ft is, that, by a certain degree of re-
fiftance, a proportion of the momentum or
force of the impingeing body is deftroyed,
and confequently of its velocity. The next
ftep is, that, with the remaining force and
velocity, an impulfe is made upon the body
at reft, which now refifts no longer, where¬
by it begins to move with the remaining ve¬
locity of the impingeing body. And the laft
ftep is, that it is carried on with the fame de¬
gree of velocity by its own vis injit a .
From
PHYSICAL and LITERARY. 31
From what is laid, it will be eafy to ad-
juft the proportion betwixt the vis motrix ,
and the refiftance of a body at reft. For
tho’ refiftance and impetus are fo effentially
different, as not to admit of a comparifon be¬
twixt themfelves; yet, the effeds produced
by them, are capable of a comparifon. Now,
the force loft by the impingeing body is a juft
meafure of the refiftance of the body at reft;
and if the momentum , before and after im-
pulfe, continue the fame ; it muft follow,
that the momentum of the body which is put
in motion, is equal to the momentum loft by
the impingeing body. Therefore the momen¬
tum of the impingeing body, is to the refift¬
ance of the body at reft, as the quantity of
matter of both bodies, is to the quantity of
matter in the latter.
This power of refiftance in matter, which
is never exerted but when an impulfe is made
upon it, is of fo lingular a nature, as to lead
us to fufped fome very artful contrivance.
It is furprifing that writers have given very
little attention to the laws of motion, con-
lidered in the light of final caufes, tho’ it is
a mod beautiful fpeculation. It would car¬
ry me too far from my prefent purpofe, to en¬
ter
52 ESSAYS AND OBSERVATIONS
ter profeffedly upon this theme. And there¬
fore I fhall barely touch upon It, fo far as
concerns this property of refiftance. Gravi¬
ty; an Unlverfal law of matter, ferves the
noblefi purpofes. In conjundtion with the
vis infita , it preferves the folar fyftem in or¬
der. The vis injiia is ufeful in another re-
fpedt ; becaufe, by its means, we can apply
force greatly fuperior to our own. The re¬
finance of bodies again, is of admirable life
to keep force within proper bounds. If the
fmallefl: body, impingeing upon the greateft,
had the effedt of communicating its own ve¬
locity, which it would do, were there no
refiftance : the fmalleft force would be fuffi-
dent to give a new violent motion to the
earth, and to put the lives of all mankind in
the power of every individual*
PHYSICAL and LITERARY, 3
Of ACTION and REACTION,
IT is laid down as an univerfal law of mat¬
ter, £C that readion is always contrary
“ and equal to adion.” Or, C£ that the mutual
<c adions of two bodies upon each other, are
€C always equal, and with oppofite diredionsA
And Sir Ijaac Newton , in illuftrating this
law, gives particular inftances of its taking
place in all the different adions of matter ;
to wit, in impulfe, in preffure, and in refin¬
ance. For my part, I have always been
puzled about this law, and am uncertain,
after all, whether I have a juft conception
of it. Are we to underftand it to be a pro¬
perty of matter in general, that when aded
upon, it exerts an equal and contrary adion ?
or only, that in thefe particular cafes where
matter reads, the readion is always equal and
contrary to the adion ? The former is Sir I-
faacs fenfe of this lawq which is evident,
from his placing it among the lav/s that go¬
vern all matter in general $ as well as from
E his
34 ESSAYS and OBSERVATIONS
his various inftances, importing that it holds
In every cafe whatever. And now, taking
the law in this fenfe, difficulties croud upon
me ; of which I fhall mention a few, that
N
make the greateft figure. The fir ft is, that,
according to this law, there cannot be in
matter, fuch a thing as refiftahce without re¬
action ; a bold aflenion, which contradicts
what appears to be the faCt in common ap-
prehenfion ; and which therefore ought not
to be admitted, without a very comp! eat in¬
duction of particular cafes *y more compleat,
fo far as 1 can learn, than hitherto has been
attempted. But, not to reft upon the nega¬
tive, it appears dear, that, in the collifion of
hard bodies, there is refiftance without rea¬
ction : and I flatter myfelf with having made
out above, that, were there reaction in this
cafe, the effects of collifion would be very
different from what they are in faCt. And
this leads to another difficulty, that if rea¬
ction were, in every cafe, equal to aCtion, viz.
in hard bodies as well as in elaftic; the effects
of collifion behoved to be the fame in both.
Two elaftic balls meeting in oppofite directi¬
ons, rebound ; becaufe, after their force is
ipent by collifion, the fame force is reftored
to
PHYSICAL and LITERARY.
35
to each, by their mutual readtion ; and the
fame mud happen to hard bodies, if they
have the fame power of reaction. In a word,
I cannot didinguifh eladicity from a power
of reaction ; and a hard body differs from an
eladic only in this, that the former has no
power of reaction, but only of reiidance.
A third difficulty is, that, in the bulk of the
indances commonly given to illudrate this
law, I cannot difcover an equality of adtion
and reaction. And ladly, what appears the
mod unfurmountable difficulty is, that, ex¬
cepting the cafe of eladicity now mentioned,
and that of fluidity to be mentioned after¬
wards; I have not found a Angle indance
of an effedt produced by the adtion of one
body upon another, but what may be fairly
explained by acknowledged principles, lay- *
ing afide altogether this fuppofed equality of
action and readtion. And if no fadt can be
condefcended on, to prove the point with
regard to hard bodies ; why ffiould we ad¬
apt this as an univerfal law of motion or of
matter ? for fureiy it is irrational to admit of
any law or principle without evidence.
These difficulties will be bed illudrated
by going to particulars. And with regard to
Sir
go ESSAYS and OBSERVATIONS
Sir Jfaacs firft inftance, of a man’s prefling
a flone with his hand; we mud diftinguilh
betwixt a moveable and immoveable obftacle9
If a man prefs an immoveable obftacle with
N *
Ills hand, I cannot here difcover any thing
but mere refiftance, which is not to be over¬
come by the force of the hand. This is an
effed which mud follow from the impene¬
trability of matter, without neceffity of ta¬
king under confideration, any other of its pro¬
perties. I difcover here no reaction. There
is no counter-achon or impulfe in the ftone,
to correfpond to the addon or impulfe of the
hand. There is nothing but refiftance, which
is indeed an addon, but an addon which
is not exerted upon the hand : the adion is
exerted within the refilling body itfelf, to
preferve it from motion. And, if this refift¬
ance ftiall be conceived as a couhter-adion,
which it may be in a loofe way of thinking;
1 cannot however conceive any equality be¬
twixt the preflure of my hand and this flip-
pqfed con nter~ addon of the ftohe. At this
rate, the counter-addon of the ftone is equal
to every degree of imprefled force, provided
the imprefled force be not great enough to
move the ftone; and fo it will be equal at
the
a
PHYSICAL and LITERARY. 37
the fame time to a thoufand different degrees
of force. To talk cf the equality of addon
and readtion in fuch a cafe, means really no¬
thing more than that the hand has not force
enough to move the ftone.
Again, if the obftacle be moveable, it
coincides with another inffance given, that
of percuffion, or the collifion of hard bo¬
dies. Here indeed it is true, that there is as
much force loft by the one body, as is gene¬
rated in the other. But then this is plainly
the effedt of the vis refijlentiae as explained
above 3 and therefore it is unphilofophical to
introduce any other principle by which to ac¬
count for this phoenomenon. At the fame
time, I cannot difcover any equality of add-
on and readdon in this cafe 3 on the contrary,
it is eftablifhed by infallible experiments, that
the impreffed force or addon is always great¬
er in a determined proportion, than the re-
fiftance or readdon. And it is this very pro¬
portion which produces the effedf of an equa¬
lity of motion before and after impulfe 3 or,
in other words, the acquifition of as much
force by the one, as is loft by the other.
Another inftance is of a horfe drawing
a ftone by a rope 3 and it is faid, that the
ftone
3S ESSAYS AND OBSERVATIONS
ftone draws the horfe as much as the horfe
the Hone. Were this To, there could be no
motion. All I can difcover here, is mere re-
fiftance in the ftone, occafioned partly by its
vis rejijlentiae , and partly by fridion. And
after this refiftance is overcome, which fpends
or exhaufts fo much of the horfe’s ftrength;
the ftone is drawn along with the horfe’s re¬
maining ftrength, without any further refift¬
ance.
With regard to gravitation, which is gi¬
ven as another inftance of the equality of a -
dion and readion; it is very true, that there
is an equal tendency in every particle of mat¬
ter to every particle 5 but I am at a lofs what
further can be made of this, than that fuch
is the law of gravitation. Why then fhouid
we endeavour to account for this effed by a-
ny feparate law ? I might add, that this at
bevft is a doubtful inftance of the mutual a-
dions of bodies upon each other. It will
perhaps, upon examination, be found the
more fafe opinion, that bodies ad not upon
each other by the power of gravity. But of
this afterwards.
KRILL , in explaining this law of na¬
ture, feems to confine it to the percuffion of
bodies ;
PHYSICAL and LITERARY. 39
bodies ; and refls it wholly upon this fadf,
that equal changes of motion are produced
upon colli fion; which is, in other words, that,
whatever force is loft by the one body, an e-
qual force is generated in the other. And
indeed it appears probable, that the law has
been invented chiefly to account for this ef¬
fect : if fo, it is extremely rafh in philofo-
phers to apply it, as they do, in every cafe
where there is the lead appearance of action
and reaction, as if it were an univerfal law
of nature that muft obtain in every cafe what¬
ever. It was not difcovered, it would feem,
that the equality of motion before and after
percuffion, is the genuine effedt of the vis
rejiftentiae. Therefore, to account for this
phoenomenon, a new law behoved to be in¬
vented; which, to difguife the matter, mull
be confidered as a general law : for, had it
been plainly fpoke out, what in effedt is faid
by Dr. Keill , that this law' applies ’only to the
percuffion of bodies; every perfon would be
fenfible, that accounting for the law of per¬
cuffion in this manner, was doing no more
than repeat ng the fadt itfelf in different
words. For to lav that the adtions of two bodies
J
in percuffion are equal and in oppofite diredti-
ons,
40
ESSAYS and OBSERVATIONS
ons, is, in an obfcure and indiftind manner,,
really faying no more, than that a force is
generated in the one body, equal to that
which is loft in the other.
N
In accounting for the preffure of fluids
undequaque, Mufchenbroke reafons thus : he
fuppofes the water in a veffel to be compofed
of perpendicular columns of fpherical par¬
ticles, one refting upon another from the fur-
face downwards, and all refting upon the
bottom of the veffel. Thus the bottom of
the veffel is preffed downwards with the
weight of a column : and, becaufe adtion
and readion muft be equal, therefore, fays
our author, the bottom of the veffel muft
prefs upwards with the fame force, i. e . with
a force equal to the weight of the column 5
whence, fays he, the whole preffure up¬
wards, muft neceffarily be equal to the whole
preffure downwards.
So far our author’s argument appears con-
clufive, that, admitting the law of adion and
readion, a preffure undequaque muft be the
confequence : and as the law is not confined
to fluids, but is fuppofed to be an univerfal
law of matter; a preffure undequaque muft
not only be the confequence in fluids, but in
folids
(
PHYSICAL and LITERARY. 41
folids equally. Here then is a fair dilemma .
We muft either acknowledge a preffure un-
dequaque in fand, powder, and indeed in all
loofe bodies, as well as in fluids ; or confine
this law of the equality of adion and readi-
on to fluids. Can we remain a moment in
doubt betwixt thefe oppofites ? We are cer¬
tain that a preffure undequaque is not a pro¬
perty of folids. The equality of adion and
readion is but an affertion without evidence.
What remains then, but that we adhere to
the former, and rejed the latter, except as
to fluids. And thus our author luckily, tho?
without intention, has furnifhed a very con¬
vincing argument againft the univerfality of
this fuppofed law of adion and readion. If
an undequaque preffure is an effed of this law,
it follows clearly, that this law takes not
place in folids, at leaft not univerfaliy, as in
fluids.
F
O F
l
42 ESSAYS AND OBSERVATIONS
Of G R A VI T Y.
RAV1TY is one of the moft remark-
vl able properties that belong to matter.
By this property, which is univerfal, every
particle of matter tends to every other parti¬
cle ; whereby, if not obftrudted, all mat¬
ter would be gathered into one mafs. As e-
very particle of matter has this tendency,
the tendencies of any two bodies to a mutual
union, mull be in proportion to their quanti¬
ties of matter. And it is obferved that the
force, which, at different diftances, is exerted
by two bodies in order to be conjoined, is in
the reciprocal proportion of the fquares of
thefe diflances. It is by this property that
the heavenly bodies move round the fun,
and are kept from flying off in a tangent :
and it is by the fame property that bodies
left free at any height, fall to the earth
with an accelerated motion. When applied
to the latter, it is commonly called gravi¬
ty 3 when to the former, attradlion . Sir
Ifaac
PHYSICAL and LITERARY. 43
f
Ifaac Newton , to whom the great difcovery
Was referved, that the defcent of heavy bo-
dies, and the curvilinear motion of the pla¬
nets, are efifefifs of the fame caufe, choofes
to talk of this property of matter with great
circumfpeftion and referve. He pretends on¬
ly, in his I rincipia, to have afcertained the
facts, without venturing to point out the
caufe. In the general cholium , which con¬
cludes that elaborate work, he fatisfi.es himfelf
with having explained “ the motion of the
“ celeftial bodies, and of the fea, by the force
cc of gravity, without aligning the caufe of
cc gravity.” He only observes, “ That gravi-
C£ ty muft be the effiedt of fome caufe, whkh
‘ C£ penetrates into the very center of the fun
cc and planets, and which afils not in propor-
ec tion to the furfaces, but the fo'id quantity
C£ of matter ; its adtion only decreafing in a
£C duplicate ratio of the diflances.” And
adds, tc That he has not been able to find
<£ out from phoenomena, the reafon of thefe
cc properties of gravity, and that he does not
C£ choofe to deal in hypotnefes.” It need not
be furpriting, that this great philofopher
fihould be referved upon the caufe of a theo¬
ry fo extenfive and fo wonderful, when it
was
44 ESSAYS and OBSERVATIONS
was his own child. New difcoveries are ah
ways received with fome degree of hefitati-
on ; becaufe it is the effed of novelty to
produce doubts as well as furprize. But
now, that this theory is fully eftablifbed by
habit, as well as by reasoning, and has got a
firm hold of the mind; it is not obvious, why
later phiiofophers mould affed the fame re-
ferve, for my part, I cannot fee any diffi¬
culty of explaining the caufe of attraction or
gravity, more than of explaining the caufe
of a body’s continuing in the fame degree
of motion with which it begins to move. And
o
this I fliall now attempt.
It is above eftablithed, that the continua¬
tion of motion in bodies muft be an effed of
a power inherent in all matter, of preferving
that degree of celerity which is once bellow¬
ed upon it. The body, by this power, is di-
reded to move in a flreight line. But we
perceive nothing in the nature of this power
to confine its operation to a ftreight line, more
than, a curve. And we may fuppofe the
power ftill further varied, to make the body,
inftead of moving in a ftreight line, or in a
curve, to dired its equable motion towards
any other given body, within a certain di-
ftanceo
PHYSICAL and LITERARY. 45
ftance. In general, as we have no means to
difcover power in any being but by the effects
produced; fo the nature and operation of the
power are only to be difcovered by the fame
means. There is nothing in our conception
of any power to confine its operations to one
law more than another. And this leads to the
caufe of gravity or attradlion. If we admit
of the vis injit a , the operations of which may
be varied in a thoufand different ways ; it is
equally eafy to conceive a power in matter by
which every particle has a tendency to be u-
nited with every other particle. JTis but va¬
rying the vis injit a in the two following parti¬
culars, to have an exadt defcription of gravity.
Firft, That it have the effedt of beginning
motion, as well as of continuing it; and, next,
That it diredl the body to which it belongs,
not in a ftreight line, but towards every body
great and fmall within its fphere of activity.
The grand difficulty which puzzles foreign
philofophers is, to admit of a power in a body
to draw other bodies to it ; for this is their
conception of attraction, fuggefted by the
term itfelf. They obferve, that fuch a power
is inconfiftent with a general maxim, that no
being can adt where it is not ; which would
involve
46 ESSAYS and OBSERVATIONS
involve this evident abfurdity, to feparate the
being from its aCtions. And, from thefe p e-
mifes, they juftly conclude, that one body
cannot aCt upon another at a diftance. It
muft be confeffed, that attraction is an un¬
lucky term, fince it has led philofophers into
the above miftake; tho’ Sir Ifaac Newton can¬
not be juftly blamed, who made ufe of a
term invented to his hand. By varying the
conception of attraction, and by confidering
it as a power in matter not to draw other bo-
dies to it, but to move itfelf towards other bo“
dies, the difficulty vanifhes.
But upon this idea of attraction or gravi¬
ty, it may be fuggefted, that there can be
no reafon, why the power, in exerting itfelf,
fhould keep pace with the diftance of the ob¬
ject towards which its force is directed. The
diftance of the objeCt, it will be faid, can
have no effeCt to diminifh the force, when,
by the fuppofition, the aCtion of the one bo¬
dy is not exerted upon the other, but upon
itfelf. This has the appearance of a difficulty,
and no more but the appearance. If matter
lias a power to aCt in any one care, its acti¬
ons may be varied by any affignable law. And
in particular to imagine a power in a body
impelling
PHYSICAL and LITERARY. 47
impelling it towards a body at hand, with a
greater force than towards one at a diftance9
is in reality not more difficult, than to ima¬
gine it exerting always the fame force, with¬
out regard to diftance.
It is not improbable, that the above men¬
tioned obiedtion, of a body’s adding where
it is not, has led Leibnitz and other foreign
philofophers, to adopt the vortices of Des
Cartes , rather than Sir Ifaac Newtons theo¬
ry ; li ffile, according to their notion of it,
to an infuperable ohjedtion. Yet there can¬
not be conceived a more whim deal hypothe¬
cs, than that of a fluid circulating about the
fun, in which the planets are involved and
carried alomr like a fhio in a torrent. The
O ' i
ingen ions Maoertuis , in his efiay upon attra¬
ction, moves feveral objedtions to it, even as
new moulded by later writers. He objedts
in the fir ft place, that the planets do not
move in a circle, but* in an elipfe. In the
next place, that they do not move with ce¬
lerities proportionable to their diftances from
the fun ; which they behoved to do, if car¬
ried along in a vortex moving, like a wheel,
equably round the fun. Thefe objedtions are
juft; but, in my apprehenfion, he has over¬
looked
48 ESSAYS and OBSERVATIONS
looked the moft folid and weighty objection*
Whatever caufe can be aligned for the moti¬
on of this fluid round the tun, will equally
apply to the motion of the planets, without
neceflity of introducing a new fund of mat¬
ter, of the exiftence of which we have no
evidence. More particularly, motion is ob-
vioufiy an effed which muft have iome
caufe. This caufe mail: either be a continu¬
ed interpofition of a voluntary agent, or a
power given to matter to continue itfelf in
motion. A piece of matter cannot move in
a ftreight line, without one or other of thefe
caufes ; and as little in a circle. Therefore,
to make this fuppofed fluid to circulate about
the fun, one or other of thefe caufes muft
operate 5 and one or other of thefe caufes is
fufficient to account for the motion of the
planets, without neceffiiy of inventing a fluid
to produce the effect. Des Cartes therefore,
and his followers, are guilty of the fame
fort of abfurd reafomng, for which we juft-
ly lairjh at the poor Indian , who was forced
to invent an overgrown elephant to reft the
earth upon, and an overgrown crab to be a
footftool to the elephant.
Whether
PHYSICAL and LITERARY. 49
Whether the fame inconfiftency of a bo¬
dy adting where it is not, has moved our
Britijh phiiofopher .to invent an aetherial
medium much rarer than air, as the caufe of
gravitation, I cannot fay. In the twenty firft
query, at the end of his optics, he obferves,
“ that this medium is much rarer within the
<c denfe bodies of the fun, ftars, planets and
<c comets, than in the empty celeftial fpaces
cc between them. And, in pafling from them
“ to great diftances, that it grows denfer and
cc denfer perpetually; and thereby caufes the
cc gravity of thofe great bodies towards one
cc another, and of their parts towards the
cc bodies; every body endeavouring to go
<c from the denfer part of the medium towards
“ the rarer.” I am not better fatisfied with
this hypothecs than that of Des Cartes . For,
without lofing time upon a minute enquiry
into the very peculiar properties with which
this fuppofed aether muft be endued, to pro¬
duce the effects affigned it; the fame obje¬
ction lies againft it, that is above urged a-
gainft the vortices of Des Cartes , that it is a
new fpecies of matter invented without evi¬
dence, and indeed without necefiity : for it
is as eafy to endue the planets with a power
G which
5o ESSAYS and OBSERVATIONS
which impells them towards the fan, as to
endue this fuppofed aether with a power
which repells it from the fun. Therefore
the argument which is juftly urged by this
author himfelf again ft a plenum in the 28th
query > at the end of his optics, may be ur¬
ged with equal fucce s again ft this fuppofed
aether, t£ It is of no ufe; and, as there is no
ct evidence for its exigence, it ought to be
ct rejected.”
I Mu ft own, at the fame time, great re-
luftance, to embrace a dodrine which over¬
turns, or fee ms to overturn, the moil; beau¬
tiful part of Sir Ifaac s own theory, and that
which affords the ftrongeft conviction of its
truth, m. the connexion, by a common,
caufe, betwixt the curvilinear motion of the
planets, and the defcent of bodies towards
the center of this earth. Suppofing an ae-
therial medium to he the caufe of the former,
it cannot well alfo be the caufe of the latter.
Among other reafons, this occurs, that the
different denfities of the fuppofed aether,
on the oppofite fides of a bit of matter left
free in the air, muft be, quam pr oxime , no¬
thing. This muft be yielded 3 and the con-
fequence is, that the bit of matter involved in
PHYSICAL and LITERARY, 51
a medium which prefles equally undequaque or
quam proxime , will either remain at reft, or
move with a very flow pace. But this is
contrary to fact ; for the acce’eration of fal¬
ling bodies, within the leafl perceivable di-
ftance, is perceivable.
The power of gravity has a Angular pro¬
perty not commonly attended to, that its
force is not fpent by being exerted upon any
Angle body. Its whole force is exerted upon
a multitude of bodies, ail at the fame time.
Thus the earth tends at once both to the fun
and moon; and the whole force of its tend¬
ency is directed to each, juft as much as if
the other were annihilated. Thus the fun is
impelled towards the whole fyftem of pla¬
nets and comets ; and its total impulfe is di¬
rected upon every one of them at the fame
inftant. It cannot fail to appear Angular
and furpriflng, to And a force exerted in io
many different and even oppofite directions
at one time, without being diminifhed by di-
viflon. Yet all this proceeds from one Angle
property, that every particle of matter tends
to every other particle; and confequently,
by encreaAng the quantity of matter indeA-
jiitely, the fum of the tendencies of any one
particle
52 ESSAYS AND OBSERVATIONS
particle of matter, may be greater than any
affignable quantity. But nature is wonder¬
ful, as well as various, in her operations; and
we ought to fubdue our incredulity, when,
upon fearching into her works, we find fo
many appearances different from wftat we are
accuftomed to in common life.
M \
Having thus eftablifhed, that there is a
power inherent in matter, by which every
particle tends to be united to every other par¬
ticle, and which power is in continual adtion
without ever being fufpended but for a mo¬
ment; the curvilinear motion of the heaven¬
ly bodies, as well as the defcent of bodies
towards the center of the earth, are obvi-
oufly the effects of this power. With regard
to any particular planet, the earth for exam¬
ple, we have only to fuppofe, that it is once
fet in motion by the hand of the Almighty;
it will endeavour to preferve itfeif in the fame
degree of motion by the vis injita . Having
like wife a tendency to the fun, theft two
powers conftantly adting in different directi¬
ons, carry it round the fun. At the fame
time, the proportion of theft two forces is
fo adjufted, that the earth, as well as all the
other
PHYSICAL and LITERARY. 53
other planets, defcribe an elipfis, in one of
the foci of which the fun is placed.
In the defcent of heavy bodies towards
the center of the earth, the force of gravi¬
ty is fuppofed to be invariable. For, tho’ this
force lefiens by diftance, yet the diftance of
any two points, from which we have accels
to drop a body, is fo inconfiderable in refped
of the diftance of either from the center,
that it is left out in all calculations as imper¬
ceptible. Hence the following queftion is
readily fuggefted, How comes it, that the
power of gravity which in this cafe is fuppo¬
fed invariable, has the effect of accelerating
the motion,of a falling body? It fhould be
thought, that the power of gravity, fuppo-
fing it invariable, muft produce an equable
motion downwards, without acceleration;
juft as the vis injit a does, laying afide gravi¬
ty, in whatever diredion the body is thrown.
For in general, as effeds muft always corre-
fpond with their caufes, every force which
is uniformly exerted without diminution or
augmentation, muft produce an equable mo¬
tion, without acceleration or retardation :
and, on the other fide, every varied effed
which
-* 4 *
54 ESSAYS and OBSERVATIONS
which is gradually diminifhed or augmented,
mu ft proceed from a varied caufe.
This difficulty is endeavoured to be ex¬
plained in the following manner. Gravity,
it is faid, has a remarkable property, ct That
ee it afts with the fame force upon a body
cc that is already in motion, as upon a body
“ that is at reft, fo as to produce equal acce¬
lerations in falling bodies in equal times
But this manner of conceiving the effedt of
gravity, whatever obfcurity it may occafion,
tends not to remove the difficulty. One thing
is extremely clear, that we have no means
afforded us, to eftimate the force of any
power, other than the effedts produced by it;
which holds in general, whether the power
be internal or external. From the uniformity
of the effedts, we conclude the vis infiia to
be a uniform power ; and we have the fame
foundation, from its varying effects, to con¬
clude gravity to be a varying power. In
fhort, when acceleration is produced by an
external caufe, it will be evident to every
one, that the force of the impulfive caufe,
muft be continually increaftng, to produce
fuch
f Mc Lanvin's account of Newton's philosophy, p . 248,
PHYSICAL and LITERARY. 55
fuch an effect ; and it will be a hard talk to
affign any juft foundation for a difference in
this particular, betwixt external and internal
force.
We muft therefore yield to the difficulty,
becaufe it is unfurmountable. It is very true,
that a body has, quam proxime , the fame
weight at the diftance of ten foot from the
furface of the earth, as at the diftance of
a hundred : and the farce of gravity is, quam
proxime , the fame when a body is drcpt from
the hand at thefe different diftances. But
then, tho’ gravity is fuppofed invariable,
where the difference of the diftances is fo
fmall; yet this only holds where other cir-
cumftances are the fame : that is, where the
body is either at reft, or moves with the fame
celerity, l or it is ext emely dear, that, in
the perpendicular defcent of a body, the
force of gravity varies every inftant, and
turns greater in its progrefs downwards.
And indeed gravity cannot otherways produce
acceleration, more than the vis infita does.
Nor is there any thing lingular in this pro¬
perty of gravity. The vis infita has a pro¬
perty fome what fimiiar : for, thoJ it conti¬
nues invariable after the body is fet in mo¬
tion,
56 ESSAYS and OBSERVATIONS
tion, yet it is not always the fame. It keeps
pace with the imprelTed force, and is very dif¬
ferent, according to the different forces with
which bodies are put in motion. In a word,
fmce effedts muft always correfpond with their
caufes, the gradual increafe of the force of
a falling body, muft infer the gradual increafe
of the power of gravity, which is the caufe
of the motion. Or rather, confidering the
matter in a different light, perhaps more ac¬
curately, the tendency or nifus of a body to¬
wards the center of the earth, which is great¬
er in motion than at reft, and which gradu¬
ally increafes with the velocity of the motion,
being nothing elfe but the exertion of its
power of gravity, makes it evident that the
power of gravity is continually increafmg
from the beginning, to the end of the mo¬
tion.
In accounting for this phoenomenon, I
have negledted the vis inftta, tho’ it may pro¬
bably adt in conjundtion with gravity in the
defcent of bodies towards the center of the
earth, as well as in the curvilinear motion of
the planets. For, if the force of gravity be
fuppofed invariable, the addition of the vis
inftta , which is alfo an invariable force, will
only
PHYSICAL and LITERARY. 57
only bring out a greater invariable force,
which can never produce an acceleration of
motion. The acceleration therefore muft be
attributed to gravity alone, the force of
which, in the beginning of the motion, is
fuppofed to be lefs than any affignable quan¬
tity, whereby a body, fet in motion by the
force of gravity, paffes through every de¬
gree of velocity from reft, till it acquire
that velocity which it has when it touches
the ground.
I have dwelt the longer upon this proper¬
ty of gravity, becaufe there is connected with
it another property, which is, that in mo¬
tion, the adion of gravity is not to be eon-
ftdered as one adiori exerted through a length
of time, but as a number of .different acti¬
ons exerted inceffantly. For, if the gravity
of a body in motion continues not the fame
any two fucceffive moments, but is continu¬
ally varying, the adion muft vary with the
power 5 and confequently is not one, but a
number of different addons. Gravity in a
body at reft, is, like the vis in fit a , one in-
varied power, which produces one in-
varied a'dion exerted through a length of
time. But, when once the body is put in
H motion.
58 ESSAYS and OBSERVATIONS
motion, we muft neceflarily admit, firft, that
gravity is exerted by repeated impulfes 5 and
next, that thefe impulfes, continually turn¬
ing fironger, form an increasing leries, hold¬
ing an exacd proportion with the growing ve¬
locity, of which thefe impulfes are the caufe.
And this leads us readily to conceive the
operation of gravity in the afcent and defcent
of bodies. A Rone, in its perpendicular mo¬
tion, is carried upwards by its vis infita coun-*
ter- able d by gravity: in its return, it is carried
down by gravity without any counter-addon.
At firft view, the afcent will be confidered
as the operation of two powers aching in op-
pofite directions 5 the effed: of which com¬
monly is, to produce an equable motion with
the difference of the forces. And, were the
addon of gravity one uniform addon, like
that of the vis infita ; fuch would truly be
the effed:: but,, as gravity is exerted by re¬
peated impulfes, a different effed: muft fol¬
low. The very firft impulfe of gravity takes
off* from the force of the vis infita ; what
remains is leftened by the fecond impulfe;
and io on, ^ till the vis infita , gradually de-
creafing by the repeated counter-addons of
gravity, be annihilated altogether. In the
return
PHYSICAL and LITERARY.
59
return downwards, gravity being exerted
without an antagonift, every new impulfe
produces an acceleration of motion ; and,
thefe impulfes being repeated inceffantly, the
acceleration goes on, till the ftone touch the
ground.
It remains only to be obferved, that, as
the force of gravity is accurately proportion¬
ed to the velocity, gravity rnuft produce the
fame effedt, whether its force be exerted in
the direction of the motion, or contrary to
it ; and that the acceleration in the former
cafe muft be equal to the retardation in the
latter, in any two points where the velocities
are equal. Thus, upon the whole, the gra¬
dual retardation of upward motion, is equal
to the gradual acceleration of downward mo¬
tion. The fame feries of numbers repre-
fents both ; a progrefs trom the (mailed to
the greateft number being fimilar to accele¬
ration; the contrary progrefs, to retardation.
And hence it is that thefe two contrary mo¬
tions are performed precifely in the fame
time.
It is now eafy to account for the different
velocities of a planet in the different points
of its orbit. The motion of a planet may
be
6o ESSAYS and OBSERVATIONS
be iufliy reprefented by perpendicular afcent
and defcent. A planet moving from the fun,
refembles a ftone moving from the earth up¬
wards ; and, in its return towards the fun,
refembles the fame ftone returning to the
earth, after its upward motion is fpent. And,
indeed, by prolonging the greater axis inde¬
finitely, an ellypfe coincides at laft with a
ftreight line ^ and the motion in the former
coincides with the motion in the latter. Con-
fidering then that gravity and the vis injita
are the two powers which govern motion in
the curve as well as in the ftreight line ; it
muft follow, that the law of motion is th§
fame in both.
PHYSICAL and LITERARY. 6t
Of the FORCE of BODIES
in MOTION.
IN explaining the firft law of motion, that
every body perfeveres, as much as in it
lies, in its prefent ftate of reft or motion; I
have touched at that remarkable power which
all matter is endued with, of moving on
with its original velocity ; and to which
power I have chofen to confine the term vis
in fit a . I now proceed to unfold fome fur¬
ther properties of this power. It appears
clear, that the vis in fit a might have been fo
ordered, as to produce an accelerated or re¬
tarded, inftead of an uniform motion. And
it might have been fo ordered as to yield to
the imalleft oppofing force, which is the cafe
of the vis refiftentiae when the body is at reft.
There is no difficulty to conceive a body en¬
dued with fuch a property, as to preferve it-
felf in its original degree of motion, where
there is no obftrudlion, and yet to yield to
the
62 ESSAYS AND OBSERVATIONS
the fmalleft refinance or oppofing force. But
the vis injit a is plainly not of this nature.
The body not only preferves itfelf in motion
where there is no refiftance, but exerts a cer¬
tain force againft every thing that refills its
progrefs. And it is with a view to this force
exerted in motion, as well as with a view to
the refiftance exerted at reft, that Sir Ifaac
Newton , in his third definition, defcribes the
vis infta to be u that power in matter, by
*£ which every body, as much as in it lies,
fi£ pe.rfeveres in its prefent ft ate of reft or mo-
tionA The force, however exerted in
motion, is effentially different from that ex¬
erted at reft. The latter is mere refiftance :
the former is an impulfive force, by which
the body endeavours, quantum in fe eft , to
overcome every obftruction to its motion .
The force of refiftance is above afcertained,
and a rule laid down for eftimating it, about
which all philofophers are agreed. They
differ widely about the impulfive force of the
vis in fit a: the Gerfnans holding it to be as the
fquares of the velocities; the Englijh and
French holding it to be Amply as the velocities.
The difpute is fpun out to a great length :
the parties, as is ufual, being more felici¬
tous
PHYSICAL and LITERARY.
tons to enforce their own arguments, than to
give fair play to thofe advanced by their am*
tagonifts. And, by profufion of writing, the
point is rendered fo perplexed and intricate,
that there appears not a better way to comeat
tne truth, than neglecting the arguments on
both (ides, to apply diredly to fads for a fo-
lution, as one would do upon a point newly
ftarted.
Con-sidering the matter abftr'adly, I can¬
not find that there is any inconfiftency in the
German hypothefis. As we may conceive the
vis infita to be exerted according to any a fig li¬
able law, fo we may conceive it to be exert¬
ed in any aflignable degree. When we con-
fider the vis infita as employed in preferving
the fame degree of velocity, it follows necef-
farily, that its force, which is the caufe, mu ft
be meafured by the velocity, which is the
effed. But when we confider another branch
or its operations, viz. its nifus to. overcome e-
very obftrudion to the equable motion, we
have no other means to eftimate this nifus,
but its effeds ; for, however probable it may
be, it does not necefiarily follow, that this
ni(u$ muft aiio be meafured by the velocity,
facts and experiments, then, are the only
means
64 ESSAYS and OBSERVATIONS
means by which we can determine this con-
trove rfy ; and, when we look about for fads
and experiments, there can be none lefs liable
to exception than thofe, where the vis injita
of one body is oppofed to the vis injita of an¬
other, by collifion and percuffion. It a pen¬
dulum of one pound weight be let down from
fuch a height, as to acquire at the loweft
point the velocity of 10, it will exadly ba¬
lance a pendulum of two pounds weight, let
down from fuch a height as only to acquire
the velocity of 5, and the two bodies will be
at reft upon their collifion. The remaining
at reft upon contad, is compleat evidence,
that the forces of the two bodies are equal ;
confequently that their forces are as their
quantities of matter multiplied upon their ve¬
locities ; and therefore that the force of the
fame body is always as its velocity,, A thou¬
sand different experiments of the fame kind,
make it evident, that the force of every mo¬
ving body is in the precife ratio of its velo¬
city. And thofe experiments muft be abfo-
lately unexceptionable, in which we compare
the force of one body, with the force of ano¬
ther equal body moving with a different ve¬
locity ; for this is in effed comparing the dif¬
ferent!
1
PHYSICAL amd LITERARY. 65
ferent forces of the fame body moving with
different velocities.
It being thus afcertained, that the force of
a body moving by the vis injit a is always in
proportion to its velocity, we have reafon to
conclude, from analogy, that the fame rule
holds where bodies move by the force of gra¬
vity. And accordingly this is alfo made evi¬
dent from a courfe.of unexceptionable expe¬
riments.
The German philofophers, in their experi¬
ments, have been milled, by afcribing to the
force of the moving body, effects which ob¬
viously remit from other caufes. Not to
lengthen out this paper too much, I fhall fa-
tisfy my felt with giving an infcance or two.
It is a fadt agreed upon, that a pendulum
fwung upwards with a double velocity, will
reach a quadruple height. Hence it is in¬
ferred by Leibnitz , and his followers, that
the forces mu ft be as the fquares of the velo¬
cities ; feeing the effedts produced by the dif¬
ferent forces, viz. the fpaces gone through,
are as the fquares of the velocities. And
could it be juftly maintained, that the fpace
run through is purely the effect of the mo¬
mentum or force, with which the body is
thrown upwards, the argument would be
X con-
66 ESSAYS and OBSERVATIONS
cpnclufive. But it is not fo. Laying afide
gravity, and the refinance of the air, a body
thrown upwards with the final left force, will
move on in infinitum < It is by the operation
of gravity, and the refinance of the air, that
motion ceafes, when the body arrives to a cer¬
tain height. The retardation, therefore, of
motion, in bodies thrown up with different
velocities, laying afide the refiftance of the
air, may be a meafure of the force of gravity,
of which it is the e fifed 5 but can never be a
meafure of the force with which the body is
thrown up, of which it is not the efifed.
And, from the fad of a body’s arriving at
four times the height with double the veloci¬
ty, to infer, that the momentum, at its out-
fetting, muft be as the fquare of the velocity,
is really not more juft, than to infer, when one
body is let drop from four times the height of
another body, that it muft acquire four times
the force of the other body, tho? it acquire
but double its velocity ; which does not af¬
ford the fhadow of an argument. When a
body is thrown up with a double velocity,
and confequently with a double force, the
reafon why it afcends four times its former
height, is plainly this, that the counteradion
of gravity, while it has a double force to
ftruggle
PHYSICAL and LITERARY. €y
RruggR with, has but half the time in any
given fpace to produce its effedt ; and there¬
fore this body, before its motion be totally
fubdued, mu ft afcend four times the height
that it afcends when thrown upwards with
the Angle velocity and Angle force.
But the argument which the Leibnitfans
truft moft to, is founded upon experiments of
the falling of balls upon clay, or other loft
body ; ‘ where it is eftablifhed, that the irn-
preffions made, are in proportion to the
heights from whence the balls are let fall,
and confequently to the fquares of the velo¬
cities. From thefe experiments it is inferred,
that the forces muft alfo be as the fquares of
the velocities ; it being taken for granted,
that the impreflions made upon the clay muft
be the meafure of the forces or momenta, of
which they are Laid to be the immediate and
diredt effects. The error of this reafoning is
of the fame kind with the former. The re¬
tardation of the motion of a body falling
through a refilling medium, is not the effect
of gravity, and therefore cannot be the mea-
fure of its force. It is the meafure of the re-
iiftance of the medium, becaufe it is the effedt
o! that refiftance. All the world knows, that
when bodies move through a fluid, or any
foft
68 ESSAYS and OBSERVATIONS
foft matter, a double force produces a qua¬
druple effect 3 which may be accounted for
in the fame manner with the retardation
which happens in the afcent of heavy bodies.
A double force makes the body afcend four
times the height before it be ftopt by the
counteradtion of gravity. And it is equally
reafonable to fuppofe, that when bodies fall
into refilling mediums, a double force will
carry the body a quadruple fpace downwards
before the motion be quite ffopt by the refill-
ance of the medium,
I fhall conclude this effay with the follow¬
ing obfervation, that the feveral powers I have
afcrihed to matter, are in nothing fimilar to
occult qualities. The error of thofe who
dealt in the dodtrine of occult qualities was,
in attributing every different effedt to feme
quality or caufe confined to that Angle effedt 3
which was in reality faying no more, than,
what all the world knows, that every effedt
muff have a caufe. This was not advancing
a fingle ftep in knowledge, but amufing one’s
lelf with words in place of things. The
powers I have attributed to matter, refolve
into general laws, each of them productive
pf 3 thoijfand different effedts. And we have
no
1 * ‘ i
PHYSICAL and LITERARY. %
no reafon to doubt that mere matter may be
endued with various powers, as well as ani¬
mals are. When we fay, that feeing, hear¬
ing, tailing, touching, fmelling, proceed
from fo many -different powers or fenfes, no
perfon confiders this as afcribing effeds to
occult caufes. Have we not the fame reafon
to conclude, that there is a power in matter
to continue itfelf in motion, another power
to refill a change from reft to motion, and a
third power to unite itfelf with every other
piece of matter ; when we perceive effeds
which as diredly refult from thefe powers, as
feeing does from the fenfe of feeing. It may
be true, for ought we know, that there is fome
more general principle in matter, which is the
foundation of all thefe powers. But ffcill it is
gaining ground, and knowledge, to trace ef-
feds to their caufes, and to difcover that many
different effeds proceed from the fame caufe„
To be diffatisfied with fuch difcoveries, mere¬
ly becaufe of the poffibility of other caufes ftill
more general, which lie hid from us, is in
effed to be diffatisfied with all knowledge
whatever ; becaufe, however far we pene¬
trate, we never can be certain, that we are
arrived at our journey’s end,
Som&
jo ESSAYS and OBSERVATIONS
Article II.
Some Remarks on the Laws of Motion , and the
Inertia oj Matter ; by John Stewart,
M. D. Fellow of the Royal College of Phy -
ficians , and Profejfor of Natural Philofo-
phy in the Univerfity of Edinburgh.
Til E Laws of motion, as delivered
by Sir Ifaac Newton , are all founded
on the fuppofition, that body of it-
felf is abfolutely inactive. And inactivity is
now commonly afcr bed to matter as one of
j
its general properties 3 body being defined
to be whatever is extended, impenetrable,
divifible, moveable, and inactive. At the
fame time, every one knows, that aCtive
powers are continually employed through all
the parts of nature. The life and motion
of animals, the production and growth of
vegetables, the attractions of gravitation and
cohefion, with other inftances of the fame
kind, are always prefent to our view*
Phi-
PHYSICAL and LITERARY.
71
Phi losophers who aflert the inactivity of
matter, ought therefore to be able to give
fome good reafon, why they refufe to allow
it the free poffeffion of fuch powers in its
own right ; and why it is only to be regarded
as a paffive inftrument, under the direction,
and fubjedt to the dominion, of fome fuperi-
or being. But, in order to afcertain the true
notion of the inertia of body, the proper
method is to begin with the fimpleft cafe;
and to confider body as a lifelefs inanimated
mafs, without weight, attraction, repullion,
or any tendency to begin motion, till added
upon by fome foreign external caufe. And
furely it would be fomewhat furprifing, if
body, even in thefe circumftances, fhouid be
found to difcover any activity.
It hath been imagined however, by fome
people, tc That, if body were utterly unactive,
cc the final left force would be fufficient to
C£ move a great body and a little body, with
<£ equal velocity : and that the fame power
cc might communicate a great velocity or a
“ fmall velocity to any body.*” Mr. De Mai -
ran in Mem. de 1' Acad. 17 28, feems to enter-
* EiTa y I. p. 9. 21, 24,
tain
72 ESSAYS AND OBSERVATIONS
tain the fame opinion, when he afks, if the
inertia of matter (which he explains to be
that refinance which body makes to its being
drawn out of reft, and receiving a determi¬
ned motion, and which is more or lefs in
proportion to its mafs) may not be the effeft
of fome motion ; and if it ought not to be
conceived as an adtual force, acting by fome
fecret mechanifm. And the author of an Ej-
Jay on Spirit lately publifhed, maintains in
like manner, that there is an active refiftance
to the beginning of motion in every body ;
tho’ indeed he attributes that activity to an
immaterial caufe. And Meff. Bujfon and
Needham too, who have carried the activity
of matter to the higheft: pitch, have drawn
one argument in fupport of their fyftem,
from the refiftance of body to motion. Need -
hams Obfervations. p.435.
To give the queftion a fair examination,
we fhall, inftead of fpeaking about matter
' or body, fuppofe for once, a fubftance before
us quite inactive of itfelf, which is extend-
ed, impenetrable, finite, and confequently
moveable. Let us try if any lefs refiftance
to motion can be expe&ed here, than is actu¬
ally to be met with from common matter.
Place
PHYSICAL and LITERARY. ;3
i ’ *
Place any mafs of fuch a fubftance at reft, It
cannot begin motion of itfelf by the fuppofiti-
on. But an adtive animated being, as for exam¬
ple, a man, can move it. Some effort muft
certainly be made, fome power exerted, to
produce this effedt. It will never be pretend¬
ed, that the fame effort Can move the mafs ei¬
ther with a great velocity or a fmall velocity 5
that being as abfurd, as to fay that a great ve¬
locity and a fmall velocity are one and the fame
thing. In like manner, it muft require one
effort to move a fmall quantity of this fub-
ftance with a certain velocity, and a differ¬
ent effort to move a great quantity with the
fame velocity. The fame energy of the a-
gent, will never ferve to move a given quan¬
tity of this fubftance, or double the quanti¬
ty of this fubftance, with the fame velocity %
no more than it will move the fame fub¬
ftance with different velocities. By this ex¬
ertion of our own adtivky, we acquire the
ideas of forces. The animated being (or
the mind) is differently affected by different
objects, whether of the ienfes or under-
ftanding. And why {liquid it be affedted
in the fame way, when a great fub-
K. ftancs
74 ESSAYS and OBSERVATIONS
ftance and a little fubftance are moved
by it, or when a great velocity and a lit¬
tle velocity are imparted to the fame fub¬
ftance ? When we endeavour to communi¬
cate motion to fueh a fubftance, we muft be
confcious of fome kind of fteeling ; and thefe
feelings muft be different in different cafes.
Thus the idea of ref ftance, as it is called, to
motion, in the moil inactive fubftance we
can imagine, would be fuggefted to us from
thefe perceptions ; and is precifely the fame
with what we experience daily in handling
of matter* Nor does it feeiii poffible to con¬
ceive an extended, impenetrable fubftance,
diverted of this kind of refiftance from iner¬
tia. The larger the fubftance is which we
intend to move with a given velocity, the
greater force muft be applied : and, could we
fuppofe it actually infinite, no finite force
could move it at all.
There is a very extraordinary paffage in
Mr. M'dauriri s Account of Sir Ifaac Newton s
Philofophy. p. 100. which, in refped of the
high merit of the author, deferves our at¬
tention* It is there faid, cc That, for ought
*c we know, matter may be of kinds fo dif-
€C ferent from each other, that the folid ele¬
mentary
PHYSICAL and LITERARY. 75
mentary particles of the one, may have a
cc greater inertia than equal folid elementary
tc particles of the other kind.” This conje-
diure, if true, would effectually overturn
what hath been now advanced. But it ap¬
pears to be equally inconftftent with his own
account of inertia , and occurs only in a poft-
humous work. The inertia of body is a
negative quality, or a negation of all pofitive
power,, and therefore can admit of no de¬
grees of greater or lefs in a given quantity of
matter. Two bodies, or two elementary
particles of equal quantities of matter, if
they are inert at all, mu ft have equal inertia ,
or require equal forces to move them with
equal velocities. And, in every cafe, the
inertia is proportional to the quantity of mat¬
ter.
If a body left at reft does not begin moti¬
on of itfelf, it is determined to remain in
that ftate, not from any real repugnance to
motion, which is as conformable to its na¬
ture as a ftate of reft : but becaufe nothing
is done without a caufe. And, when adted
upon by any external influence, it obeys
without reludtance ; the motion produced
being in exadt proportion to the moving
caufe.
76 ESSAYS and OBSERVATIONS
caufe. It has a conftant fufceptibility of mo¬
tion, and a per fed: facility in receiving it.
Bat we may as well afk, why an inactive
fubftance does not begin fome degree of mo¬
tion of itfelf? as, why different powers are
requifite to produce different motions? When
people talk of the refill mice of matter at reft,
as of an aBive power > draggling againft any
agent, and actively opppfing it, they farely
frame to themfelves fome notion of force an¬
tecedent to all experience 5 and, they would
do well to inform the world, in what man¬
ner this idea was fuggefted to them.
The pajjive nature of body is abundantly
manifeft, from its yielding to the leaft con¬
ceivable adlion. The leg of a fly moves the
whole globe of the earth. A man indeed
cannot roll a tun fo faft as he can a tennis-
ball : and we may find a horfe able to draw
a loaded cart two miles in the hour, who
cannot be prevailed upon to draw it four
miles in the fame time. But are not fuch
common phaenomena as thefe more natu-
a
rally accounted for, from the fluggifhnefs or
Inactivity of matter, than from its fnppofed
activity ? A great body fet in motion is one
effedt 3 a little body moved with the fame
velocity
PHYSICAL and LITERARY.
//
velocity is another. A given body moved
With a great velocity, is one effeCt; and, when
moved with a lefs velocity, it is a different ei>
fed:. The old principle feems to apply well
enough in this cafe, that effects are proporti-*
onal to their caufes.
It muft be confeffed, that authors in
treating of the inertia of matter, and of its
refinance to motion, are very apt to exprefs
themfelves in terms that import a real activi¬
ty ; and which, if ftriCtly underftood, are
inconfiftent with inertia . Thus, when a per-
fon in a boat pulls a rope that is fattened to
the fhore, it is commonly faid, that the man
aCts upon the fhore in one direction, and that
the fhore, by its reaction in the oppofite di¬
rection, pulls the man and boat towards it.
Yet, notwithftanding fuch expreffions, will
any one ferioufly maintain, that the ground
has an active power to produce any fuch ef¬
fect?' It is evidently the force of the man
extending himfelf, that draws the fhore with
his hands one way, and at the fame time
pu flies the veffel with equal force with his
feet the oppofite way. In like manner, if a
perfon handing in a boat, pufhes againft the
ground with a pole, it is not really the rea-
78 ESSAYS and OBSERVATIONS
dtion of the ground that makes the boat re¬
cede; it is the force of the man that is the
only moving power, adting equally upon both
the boat and the ground. When a boat is
rowed with oars, the oars are faid to adt up¬
on the water in one diredtion, and the water
to readt upon the oars in the oppofite diredti¬
on, and to produce the motion of the boat*
Yet it is plain, that the motion is intirely pro¬
duced by the rower, who, in fo far as he
contributes to the motion of the boat, em¬
ploys the oar as a lever of the fecond kind*
where the body to be moved, or the boat,
is placed betwixt the moving power and the
fulcrum .
In the common account of the progref-
fion of animals, whether it be of walking,
flying, or fwimming, Borelli and all other
authors content themfelves with telling us.
That the animal adts upon the ground, air,
or water, in one diredtion, and that the rea¬
ction of the medium carries the animal for¬
wards in an oppofite direction. This is at
belt but too concife, not to call it a falfe the¬
ory: feeing it mult be manifeft that the me¬
dium, by any readtion which takes place
here, can only confume as much force as is
impreffed
PHYSICAL and LITERARY. 79
imprefied upon it, and is utterly incapable of
producing any kind of motion. The only
immediate caufe of the motion, being the
active force of the animal which preffes the
medium one way, and its own body the o-
ther way, as might be particularly fhown in
every kind of progreffion, if it were thought
needful.
Thus, upon the moft attentive examina¬
tion into the Rate and condition of body at
reft, we have found it to be perfectly inert or
inadtive. Body in motion next demands our
confederation. Suppofing a body once put in
motion by fome agent or other, it behooves us
to follow it out, and enquire what happens
to it on this change of its ftate. An extend¬
ed, impenetrable, inactive fubftance has re¬
ceived a motion : Will it inftantly ftop when
the immediate influence of the adlive power
ceafes l or will it perfevere in its new ftate ?
From what commonly happens in the
motions of bodies, their gradual lofs of force
and returning to a ftate of reft ; people con¬
tract an early prepofleftion, and are ready to
imagine, that reft is the proper ftate of body*
But a diligent review of all the circumftan-
ees, foon difcovers, that body is equally in¬
different
So ESSAYS and OBSERVATIONS
different to either Rate, of reft or motion *
Body at reft does not change its Rate of itfelf*
no more does body in motion. A body at
reft requires no caufe of its continuance j as
little does a body in motion, inis property
of body, by which it perfeveres in its ftate
of reft, or of uniform motion, in a (freight
line, unlefs when forced to change it by fome
external influence, is called the inertia of
matter.
We know not how motion is originally
communicated at all ; we know nothing of
the nature of motion or force, but by expe¬
rience. We can define neither 5 the ideas
being quite Ample. Natural philofophy
however takes it for granted, that fuch a
thifip- there is. Let a motion or force begin
any way you pleafe, we never fee it ceafe
till it be deftroyed. Why then fhould we
imagine a body ought to (lop of itfelf ; and
that, to preferve it in motion, a conftant exer¬
tion is neceffary, like that which produced it
at firft ? What argument can lead us to a-
feribe fuch an activity to body? What fhould
determine the body to flop, if there be no¬
thing to oppofe its motion? Is there any
experiment pointing that way ? yes, <c we,
mav
PHYSICAL and LITERARY- 81
sc may be defired to refied on what a perfon
cc feels within hrmfelf in walking, during
<c which a repeated adivity is exerted to con-
5f tinue the motion But this, furely, c^rt
only be intended as an illuftration of what is
meant by the fuppofed adivity of matter ill
motion, and not as a proof of its reality. For*
every day’s experience muft teach us on the
contrary, that it requires a great adivity,
fometimes more than we are mafters of, to
flop a begun motion in our bodies. How
doth it appear, that the fame effort is necef-
fary to be continually exerted, which was
employed at the beginning of the motion ?
We find a certain effort neceffary to begin a
motion in our own bodies 3 but, we fhould
find no occafion for repeating it, were it not
confumed or wafted upon other bodies. When
we give ourfelves one pufh forwards upon a
fmooth furface, fuch as ice for example,
there is no need for a fecond immediately 5
and, were there no attrition nor refiftance
from the air, the motion would continue for
/
ever. If a body fet in motion, were to flop,
retard, or any way change, its motion of it«
L felf ;
* Effay I. p.
82 ESSAYS AND OBSERVATIONS
felf; that would betray an inclination or ten¬
dency to one Hate preferably to another; it
would no longer appear equally indifferent
to either, in which alone paffivity confifts.
The mold general law of matter we dis¬
cover by experience is, that every effed con¬
tinues till deftroyed by fomething. Why then
may not motion continue till it be deftroyed,
as well as the magnitude, figure, colour, or
any other property of body ? or even as well
as the very exiftence of matter? “ Motion
€C is indeed a mode of exiftence different
cc from all others, nor can we compare it to
cc any thing that is not motion ?*.” But that is
no reafon why it fliould change of itfelf, any
mbre than thefe other modes. If the conti¬
nuation of motion bore a nearer refemblance
to the continuation of any other effed3 would
that render it any plainer ? Motion is an effed
fui generis but we have an infinite variety
of examples of its continuance. An adive
being preffes forwards a certain quantity of
an impenetrable inadive fubftance : is there
not feme effed produced here ? fomething
then communicated to it ? The body is put
in
* EfTa y I. p. x8. 19.
PHYSICAL and LITERARY. 83
in motion : why ought that motion to ceafe
without a caufe ? Adion is neceffary to the
produdion of motion, and no wonder if no¬
thing can deflroy the effed of one adion but
another adion. The trite maxim, fublata
caufa , tollitur effeffius, is not to be fo literally
interpreted, as that an effed may not conti¬
nue, after its caufe ceafes to ad.
As we know fo little of the nature of that
influence by which one being puts another
in motion, or by which it excites motion in
itfelf ; with what reafon can we pofitively
conclude its effeds to be- only momentary,
when they every where appear to be fo per¬
manent ? When motion is begun in any body,
we attribute it to a certain adion which we
cannot poffibly explain ; when a body conti¬
nues in the motion which it has once recei¬
ved, it appears to be a neceffary confequence
of that adion. We commonly indeed fay,
that the body then moves on of itfelf; but the
only queftion in debate is, W hether there be
occafion for a continual recruit of force, new
impreffions, new follicitations to motion,
like to what were at firft exerted by the mo¬
ving power. '
Unless
V
*
84 ESSAYS and OBSERVATIONS
Unless this account of the continuation
of motion can be fhewn to involve feme ab-
furdity, why fhould we feek for any other
caufe of it, than the force irnpreffed by the
external agent ? We may be told perhaps,
C£ That motion is a continued addon and
*
therefore body continuing to move, is active*
But is not this either a begging of the que-
flion, or taking hold of the ambiguity of
language to fupport it 3 inflead of explain¬
ing, why a motion once excited fhould ceafe
of itfelf? No doubt, we commonly fay in
the mechanical philofophy, that one body
ads upon another by impulfe, and the other
reads upon it. Nay, Sir Jfaac Newton him-
felf fpeaks of matter ading by inertia , or
f vis inertiae , which, tranilated literally, would
feem to import an impotent power, or adive
inadivky. Such terms cannot eaiily be avoid¬
ed, without introducing endlefs circumlocu¬
tions. If more accurate expreffions can con¬
veniently be fubftituted in their place, it
would be no differvice done to philofophy.
But we are not to difpute about words, when
the meaning is clear ; or, to confound things
entirely diftind, becaufe they happen fre¬
quently to be called by the fame name. The
true
PHYSICAL and LITERARY. 85
true diflincEtion between adive force, proper¬
ly fo called, and the vis inertiae , feems to con-
hit in this, that feme beings can begin mo¬
tion where there was none before, either in
themfelves, or in the body to be moved : in
other beings, the motion, when begun from
fome external caufc, is continued for want of
a power to Rop it. The firft of thefe may
be properly denominated active beings ; the
other, even when in motion, have no proper
activity of their own.
There can indeed be no action upon mat¬
ter without a production of motion, or at
lead: a tendency to it. Rut it doth not there¬
fore follow, that motion and addon are fyno-
nymous terms. Why may “not an adive be¬
ing communicate motion to matter, without
moving itfelf ? Is not that every whit as eafy
as felf-motion ? Rut, whether the agent
moves itfelf or not, it muft have a poveer of
ading, previous to all motion; otherways it
would be impofiible for matter or any other
being to begin motion of themfelves. A due
attention to this remark, will afford a dired
anfwer to what hath been fo much infilled
on, £C That motion is adion.” Motion is not
adion, but the efted of an adion.
• 1 1
Adiyity
$6 ESSAYS and OBSERVATIONS
Activity may be varioufly applied. An adl-
on may be with-held by an oppofite and equal
adion, as in the cafe of two contrary preflures:
or, it may be employed in deftroying the ef¬
fect of fome former adion, as when it flops
\
or retards a moving body. But the genuine
charaderiftic of an adive being, is a power
of beginning motion either in itfelf or ano¬
ther, without the means of preceeding mo¬
tion Thus a man from a ftate of reft can
begin a motion which fhall move another
body : or he can begin a motion which fhall
flop or retard another motion. And it will
readily be admitted, that whatever adive be¬
ing can thus begin motion in another, without
the means of previous motion, will of courfe
be able to confume motion in another, with¬
out receiving any itfelf.
W hen one body ftrikes upon another and
moves it, we commonly indeed call this an
adion : yet there is no refemblance between
this mechanical communication of motion,
and
* All mere mechanical communications of motion , are not
properly adion, but mere pajji<venefs, both in the bodies that
impel!, and that are impelled. Adion is the beginning of a
motion where there was none before, from a principle of
life or activity. Clarks Lett . to Leibnitz, p. 327.
PHYSICAL and LITERARY. 87
and the activity before defcribed. This is
conceived to be an adion in a fecondary
fenfe. It is only a confequence of the firft
adion. A motion once produced continues,
till it be deftroyed by an equal and oppofite
motion, or an adion capable of having pro-
duced it.
The effed produced by an agent is a cer¬
tain quantity of motion or force, which, like
other efteds, continues without any tenden¬
cy to perifti of itfelf. This quantity of mo¬
tion, is always proportional to the real fpace
defcribed by the whole quantity of matter ;
and that fpace having length, breadth, and
thidcnefs, is meafured by multiplying the
quantity of matter, by the length of fpace
defcribed by every particle, that is, by the
velocity. If a body in motion ftrikes dired-
ly upon another at reft, the two move on as
one body after the ftroke. , They cannot move
together with the fame velocity that the An¬
gle body had before the ftroke, for then there
would be an increafe of quantity of motion.
And whence fhould that proceed ? fuch an
appearance as that, would difcover an adivi-
ty in bodies indeed. Upon the fuppofition
or perfed inadivity, the quantity of motion
mu ft
88 ESSAYS and OBSERVATIONS
muft remain unchanged : and we here abi-
trail entirely from elafticity, whofe effects
proceed from a real activity, and have no re¬
lation to what is called the vis inertiae. To
find the length of the fpace defcribed by the
impinging body, we divide the fpace by the
quantity of matter, which is as it were the
bale. And to have the length of the fecond
fpace defcribed by the two bodies conjointly,
we muft divide the fame fpace by the
mafs of matter in both. As the divifor in-
creafes, the quotient muft diminifh in the fame
proportion.
Were we indeed to examine very minute¬
ly the gradual communication of motion
from one body to another, we fhali find a
real activity concerned in the operation ; but
then it is not of that fort againft which we
are now contending. It is that active force
known by the name of the attraction of cohe -
fion , which there takes place. When any
part of a body is pulled or {truck upon by
any moving power, it would neceffarily be
feparated from the other parts, were there
no cohefion. But, where there is a cohefion,
that attractive force muft oppofe the moving
power. And if either the cohefion be flrong,
or
PHYSICAL and LITERARY. 89
or the velocity of the moving power but
fmall, this oppofition muft continue, till
fuch time as all the parts of the body have
acquired one common velocity. That part
of the body which is immediately aCted up¬
on by the moving power, is firft put into
motion; and, drawing the other parts alter
it, gradually communicates motion to them,
without ever getting beyond the reach of
their attraction, or being broke afunder. Yet,
it is ftill to the moving power that the motion
of the whole body muft be aferibed ; became
the attraction among the fmall particles be¬
ing mutual, will oppofe the motion one way,
as much as it promotes it the other ; and fo
can neither forward nor obftruCt the motion
upon the whole. The attraction ferves only
to conneCt and link the feveral parts together.
The force loft by one body, is precifely c-
qual to what is gained by the other 5 the
whole effeCt or change, with regard to mo¬
tion being the fame, as if it had been in-
ftantaneoufly produced. And there is no ar¬
gument to be drawn from hence, to prove
the aCtive refiftance of one body at reft, to
another in motion, or the tendency of any
body in motion, to return to a ftate of reft.
M From
5TO ESSAYS AND OBSERVATIONS'
From the experiment of Mr. Poleni we
learn, That fpheres of equal diameters falling
upon foft clay, make equal imprefiions, when
the prod lifts of the quantities of matter into
the heights from which they fall, are equal *
that is, when the quantities of matter multi¬
plied by the fquares of the velocities are e-
qual. As it is much eafxer to determine
when two imprefiions are equal, than when
they differ in any proportion of magnitude;
the velocities of the different bodies in this
experiment, are fo admitted, in refpeft of the
quantities of matter, as that the imprefiions
may be equal. But, from thence we con¬
clude, that fueh imprefiions are always as the
quantities of matter and fquares of the velo¬
cities conjointly ; and confequently, when
the quantities of matter are equal, the im¬
prefiions will be as the fquares of the veloci¬
ties. The fame experiment may be (hewn
•perhaps in a more Ample manner, by making
pendulums of different quantities of matter,
to ilrike with different velocities upon a
fmooth fur face of foft clay ; the velocities
being always afligned by help of a graduated
arch, as is done in the common experiments
of the collifion of bodies. In this manner, -
likewife.
PHYSICAL and LITERARY. 91
like wife, the impreffions are found to he e-
qual, when the products of the quantities of
matter, by the fquares of the velocities, are
equal. Thus, let a hollow ball, with a
quantity of matter 1, move with a velocity
20, and make a certain impreffion. If you
afterwards* inclofe as much lead within the
fame ball, as to render it of double the mafs
of matter; you mufl give it a velocity fome-
what exceeding 14, before it make an im¬
preffion equal to the former one. If the bo¬
dy 2, receive only a velocity 10, the impref¬
fion will be remarkably lets. In the former
method, the gravity or weight of the balls,
continuing to ad after they touch the clay,
may contribute fo me what in making the im¬
preffions; but, in the other way of proceed¬
ing, the impreffions muft be more exadly
owing to the vis injit a , or force acquired by
the bodies, in falling from the determined
heights. This experiment can ealily be re¬
conciled with the old meafure of forces, ac¬
cording to which the forces of equal bod’es
are to be eftimated from the velocities limply.
But, in order to do this, we ought carefully
to diftinguilh betwixt two very different kirn s
of refiftance, viz . that from the inertia of
the
92 ESSAYS AND OBSERVATIONS
the matter, and the other from the force of
cohefion. When an impreffion is made by
a ftroke, upon the forface of any yielding
fuhftance, fuch as foft day ; the refiftance to
be overcome in making that impreffion, pro¬
ceeds almoft entirely from the tenacity or co¬
hefion : any refiftance arifing from the inertia
of the fmall quantity of matter difplaced in
forming the pit or cavity, is quite inconfider-
able. The force of cohefion or attraction
amongft the feveral particles of any homoge¬
neous body, is equal and conftant; and there¬
fore, muft produce an uniform refiftance to
the motion of any body applied to overcome
it, or a refiftance proportional to the time of
the aCtion. The continued refiftance of a
few attracting particles in a flow motion, and
the fucceffive refiftance of a greater number
of particles in a quick motion, will equally
diminifh the force of a given fpherical body,
in an equal time. If then the force of any
ball, moving with a certain velocity, be con-
fumed by the refiftance from cohefion in a gi¬
ven time; the force of the fame ball moving
with double velocity, will be confumed in a
double time ; if the velocity be triple, the
time will likewife be triple 5 and the veloci¬
ty
PHYSICAL and LITERARY.
9 3
ties muft always be proportional to the times
in which they are deftroyed. From whence
it is manifeft, that a ball finking with a velo-
city as 2, muft make an impreffion fourfold
of what it makes with a velocity as i • be-
caufe it continues likewife for double the
time. In uniform motions, a double veloci¬
ty and a double time, muft always give a
fourfold fpace : and the fame thing muft ob¬
tain in equably retarded motions 3 the fpaces
defcribed being exadtly the half of what
would have been defcribed by the uniform
motions. But, tho* the impreffion be four¬
fold, the real effeft, by which the force ought
to be meafured, is only double ; for it has on¬
ly undergone a double refiftance. For the
fame reafon, triple the velocity makes a nine¬
fold impreffion. And, in general, the fmall
impreffions made upon the furface of loft
clay, (or even upon marble) by bodies lin¬
king upon it, muft, caeteris paribus , be, as
the fquares of the velocities. Thefe impref¬
fions, made in oppofition to the uniform re¬
fiftance of cohefion, are no better meafures
of forces, than the heights to which bodies
are thrown near the earth, in oppofition
to the uniform power of gravity. The
Jieightg
94 ESSAYS and OBSERVATIONS
heights are known to be, as the fquares of
the velocities. When the velocities are, as 2
to i, ah heights are, , as 4 to 1. But the
forces ire Hill to be eftimated, as 2 to 1 5
fince the times which the uniform a&ion of
gravity tafes to deftroy them, are in that
proportion. With a double velocity, and in a
double time, the body arives at a fourfold
height.
What hath been here remarked, con¬
cerning the meafure of forces, is not fo
much intended for the inftruftion of thofe
who have had leifure to attend to this cele¬
brated controverfy, as to enable every one
who has the fmalleft acquaintance with thefe
matters, to lodge for themfelves; whether the
common arguments, when rightly underftood,
be fufficient for the decifion of the queftion P
or, whether there be ftill occafion for a new
folution of the difficulties ? The debate has
been clofed long ago ; after being managed by
the ableft advocates on both fides : and the
fubjedt is generally thought to be exhaufted,
though no formal reconciliation hath hitherto
been declared arnoneft the parties. We are
now told, C£ That by a profufion of writing,
the point is rendered fo perplexed and in¬
tricate.
PHYSICAL an d LITERARY, 95
“ tricate, that there appears not a better way
ct to come at the truth, than, neglecting the
<c arguments on both (ides, to appV, direCtly
“ to faCts for a lolution, as one would do up«
“ on a point newly darted,” With this pom¬
pous introduction, or preamble, is ufhered
in a new projeCt for a treaty of peace amongd
the Englijh , French , and German philofophers*
No mention is made of the Italians , the
Dutch , and others, tho’ they were pretty
deeply engaged in the quarrel. The reafon
for which omiflion may poffibly be this, that
the philofophers in Italy y Holland and elfe-
where, chufe rather to preferve the appear¬
ance of neutrality, and aCt as mediators,
A preliminary article being fird fettled, name¬
ly, to confider the feveral pretenlions of the
contending powers, as (o many points newly
Jlarted , and that without any regard to their
refpeclive memorials ; there arofe a neceffity
in the next place, in order to render the ne¬
gotiation the more confident with itfelf, for
Jlarting new faCts like wife, or at lead of new-
modelling the old ones. The method in
which the whole affair hath been conduc¬
ed, and the jarring and oppofite intereds ad-
juded, will bed appear by an indance or
9 6 ESSAYS and OBSERVATIONS
two. It is faid, That when a body is
thrown up with a double velocity, and
confequently with a double force* the rea-
fon why it afcends four times its former
C£ height, is plainly this, that the counter-
sc adfcion of gravity, while it has a double
€€ force to ftruggle with, has but half the
“ time, in any given fpace, to produce its ef-
C£ fedt.” The natural meaning of which is,
that if a body, thrown up with" any velocity,
riles to a certain height in a given time * a
body thrown up with double the velocity,
ought to afcend to an equal height in half
that time. This indeed would hold true,
if the upward motions could be fuppofed u-
niform : but, as a body thrown up, happens
always to be equably retarded, the real fadt
comes out to be very different. The body
thrown, up with the double velocity, rifes to
triple the height of the firft body in an equal
time, and to f of that height in half the
time. Let the height to which the firft bo¬
dy rifes in any time, be called i yard * the
height to which the fecond body afcends in
half that time, is i yard and f. The for**
mer pofition however, as it was only taking
a retarded motion for an uniform one, was
pretty
PHYSICAL and LITERARY. 97
pretty plauiible, and good enough to pafs up-
' on Germans and other foreigners 5 efpecially
if they were ftrangers to the Englijh language,,
Another allowable artifice to deceive the ad-
verfaries, is in endeavouring to make them
believe, that “ all the world knows, that
u when bodies move through a fluid, or
<c any foft matter, a double force produces a
“ quadruple effedt.” If the word effeffi were
taken in its mcft proper fenfe, for the force
communicated to the fluid or foft matter, by
the moving body, this could never exceed
the force of the body. A double force could
never produce any more than a double effedt
in its own direction. All the world indeed
may know, that when a body ftrikes upon
clay or other fuch foft matter, a double force
may produce a quadruple impreffion. But
then, this can only happen in fuch cafes,
where no other refiftance is worth the mind¬
ing, but that arifing from the cohefion of
the matter, in the manner above explained.
When a ball moves through a fluid, the re¬
fiftance proceeds, almoft entirely, from the
denfity or inertia \ and, the denfity being gi¬
ven, this refiftance muft increafe as the fquares
of the velocity. In this cafe, it would be a
» N vain
9 S’ ESSAYS and OBSERVATIONS
vain attempt, to affign any meafure of the ini-
preffions; hecaufe, it follows clearly from the
demonflrations of Sir Jfaac Newton that
the body would go on for ever. And furely,
it requires not much abflradt reafoning to
prove, that meer inertia , without the help
of feme adlive power, like gravity, or the
attraction of cohefion, could never totally
confume any motion, or reduce a body from
a Rate of motion to a Rate of abfolute refl.
Yet, after all, as every one has heard, that
the reflflance of a perfeft and incompreffible
fluid, was in the duplicate ratio of the velo¬
cities; this was foundation enough for a lover
»
of peace, to aflfert roundly, that the impref-
iions made in a fluid, were in that ratio like-
wife. Greater Rretches might well be per¬
mitted for the accomplifhment of fo defirable
an end, as a compleat union and harmony a-
mongfl philofopliers.
When one body Rrikes upon another with
a great velocity, the parts immediately im¬
pelled, are fometimes broken off or driven
away beyond the reach of attraction, before
they have time to draw the other parts after
them with any obfervable force ; and the
force
* Princip. Lib. II. Prop, v, et cor.
99
PHYSICAL and LITERARY.
force of cohefion, having oppofed the im¬
pinging body for fo fhort a time, makes no
fenfible refiftance to it. The attraction of
cohefion ading without interruption ; any
refiftance made, or any motion communica¬
ted by it, mult be gradually produced; and
confequently, in a very frnall time, the ef-
fed will be proportionally frnall. Of this we
have many examples. Let us fuppofe a board
fet nearly upright on its end, and fo flightly
fupported, that a bullet thrown againft it, out
of a man’s hand, will tumble it over ; if the
fame bullet be difeharged from a gun, it will
go through the board without moving it out
of its place. In the fame way, a bullet has
been known to go through a man’s body, an
arm has been taken off by a cannon ball, or
even by the fail of a wind-mill, without any
vifible motion produced in the other parts of
the body; though a much lefs force would
be fufficient to drag the whole body forwards.
The better to illuftrate the manner in which
thefe effeds are performed ; let it be obfer-
ved, that by means, of a frnall thread or a
load-ftone, a confiderable mafs of matter
may be gently pulled alongft a table: where¬
as, if a fudden tug be given, or a greater
force
100 ESSAYS AND OBSERVATIONS
force applied; the thread breaks, or the load-
Rone feparates, without feeming at all to
move the body. The nature of inertia and
-refiftan.ee has been fo much mifunderftood,
or mifreprefented, that it was neceffary to
explain thefe phaenomena from their true prin¬
ciples. In particular it might be thought,
confidently with the falfe notions advanced
concerning the refiftance of matter, that the
reafon why a body did not move forwards
when a part of it was broke off by a great
force, was this, that the inertia or refiftance
to motion in that cafe, became ftronger than
the power of cohefiom
Philosophers have fondly perplexed them-
felves, with many fubtile queftions con¬
cerning the communication of motion; and
have perfifted, with the utmoft anxiety, in a
a very fuitlefs enquiry, how motion can pafs
out of one body into another : as if motion
was fomething that could be feparated from
the moving body, and infufed from one into
the other, like water poured into a phial.
But, notwithftanding all the intricacy of this
affair, it would appear to be ftill a greater
myftery, if one body in motion were not to
?nove another lying freely at reft. It is in¬
deed
PHYSICAL and LITERARY, ioi
deed only by experience that we learn the
laws of the communication of motion. For
who ever fuppofed, that either the general or
particular properties of matter could be dif-
covered in any other way? Flow could it be
known, whether body was penetrable or im¬
penetrable, diviflble or indivifible, elaftic or
non-elaftic, animated or inanimated, but by
trial? Suppoftng however, that we were in¬
formed before-hand, that the body at reft
was impenetrable, utterly inactive and foft,
and had neither impediment nor tendency to
motion ; what would hinder us to foretell
exactly every circumftance that happens,
when another body of the fame kind ftrikes
upon it * ?
When a body in motion ftrikes upon ano¬
ther at reft; the one lofes as much motion, as
the other gains, in the fame diredion. This
is ordinarily faid to proceed from a readion
of the body that acquires the motion. The
effed is indeed the fame upon the percutient
body; there is the fame change of its ftate,
as if it had adually received an impulfe in
the contrary diredion. This, for the fake of
fhortnefs,
* r
•* Phi!of. Effay?t
i
102
ESSAYS AND OBSERVATIONS
ihortnefs, we may, and always do call, the ejfeSi
of r eaSt ion ; but we can never imagine that
there is any real adive oppofition of the bo¬
dy at reft to the motion of the other. The
great difficulty complained of, is in concei¬
ving;, how the one body has its motion dimi-
nifhcd by the ftroke as much as the other is
increafed, while there is no adive repugnan¬
cy allowed in the one to tne other. It would
be ridiculous enough to fancy, that the mo¬
tion of the one was a pait oi tne motion or
the other ; and that the very fame motion
could be transferred from the one into the
other. “ As well might the magnitude, fi-
« gUre, or colour, of one body be imparted
<t t0 another.” But this we may venture to
fay, that, for ought appears to the contrary,
it follows from the nature of a paffive, ex¬
tended and impenetrable fubftance, that mo¬
tion is loft in one by producing it in another.
It will eafily be admitted, that one motion
may deftroy an oppoftte motion, and by that
means loie oi its own. r Cl tneie is no leis
difficulty here, than in the communication of
motion. If two pieces of clay oppofing
each other with equal forces, had any real a-
divitv of .their own, it might be expected.
PHYSICAL and LITERARY. 103
that, tho’ they both ftopt at their firft meetings
this was only done by fufpending the effedt
of each other’s adtion ; and that they would
relume their former degree of motion, upon
being feparated by a man’s hand. We find
however, that the motion of both bodies is
irrecoverably loft by fuch a collifion. If then
the force of one body is loft or confumed by
deftroying force in another ; why may not
one body as well lofe force by producing it
in another. Befides, were there any real a-
dlive oppoiition in the body at reft, to the
body in motion 5 part of the force ought to
be loft on that account, and the fum of the
motions after the ftroke, would be lefs
than the motion before it.
Vv hen a horfe pulls a ftone forwards, it is
commonly faid, that the ftone pulls the horfe
back, with a force equal to that with which
the horfe pulls the ftone forwards. But no¬
thing more can poftibly be meant, than that
the horie lofes as much force as the ftone
gains : and that, with refpedt to the horfe,
the effedt is the fame, as if there was no
ftone tied behind him, but that he was pufh-
ed back with a force equal to that acquired
by the ftone. The adlive force of the horfe’s
limbs
J04 ESSAYS and OBSERVATIONS
limbs prefles forwards both the horfe and the
ftone; what is called the reaction of the ftone,
is not equal to the whole force exerted by the
horfe ; for then indeed there could be no
progreffion : it is only equal to what is im-
prefled upon the ftone.
The equality of aftion and reaftion in the
cafe of preffures, is to be underitood in the
fame manner. When a finger is prefifed a-
gainft any body, the body is (aid to react
upon the finger, as much as the finger is
made to aft upon the body. If the weight
of the body be fuftained by the prefiure of
the fineer, there will be an aftive refinance
o '
from the power of gravity. And, if the fi¬
gure of the body be violently kept in a bent
or compreffed Rate, there will be an aftive
refiftance from the caufe cf cohefion. But
if the finger be applied fo as to communicate
an equal motion to all the parts of the body,
and without oppofing its gravity; there will
be no occafion for imagining, that the body
really reafts, or aftively bears againft the fin¬
ger. The effeft indeed upon the finger is
the fame, as if the body aftually prefled up¬
on it; but that e fie ft can eafiiy be accounted
for, without having recourfe to inch a fup*
pofltion.
PHYSICAL and LITERARY. 105
pofition. The furface of a foft body, like
that of the finger preffed againft a hard body,
muft undergo a change of figure, and receive
the fame impreffion, as if the hard body was
preffed againft it ; becaufe, when the parts
that come fir ft into contaCt with the body
have their motion retarded, the other parts
will advance farther forwards.
If there was any contradiction or abfurdity
in the common opinion of the communica¬
tion of motion, this would be a fufficient rea-
fon for rejecting it, tho’ it were ever fo a -
greeable to the natural appearances of things.
But fhall we maintain, that every particular
body can only be moved by a power of its
own 1 and fhall we deny, that motion is com¬
municated by one body to another, meerly
becaufe we do not underftand the precife
manner in which motion is either conveyed
or preferved ? Why do we not, for the fame
reafon, deny, that motion is begun at the
command of any animated being ? Or do we
better conceive how any being or body moves
itfelf, than how it moves another ?
xYn appeal has been offered to the com¬
mon fenfe of mankind, as ready to declare in
favour of the a&ivity of matter. If the facts
O be
to6 ESSAY'S and OBSERVATIONS
be fully reprefen ted, the public judgment
need not be declined. Whatever obfcurity
the learned may find in this fubjed of the
communication of motion, a vulgar obferver
will be very little perplexed about the matter.
When a ftone is thrown out of the hand, and
continues to move when left to itfelf ; there
is no fear, but tc every perfon, who has not
C£ ft u died philosophy,5’ will rather attribute
this to a force fome how imp Defied upon the
ftone, than to any adion or operation of
the lifelefs ftone. It will never enter into
his head, that the ftone flies away with
wings of its own. Such a perfon, judging
from firft appearances that all motion lan-
guifhes and decays, may, likely enough, be
inclined to think that body rather affeds a
flats of reft than a ftate of motion ; and that
the imprdfed force would not remain for e-
ver : but he will never entertain the fmalleft
doubt, but, that as long as the motion con¬
tinues, it is only an effied of the firft impulfci
And, h aving once granted that motion can
continue one moment as an effed after the
adion of the moving power is over, the fame
reafon muft remain for its continuance the
next moment of nme, and fo on forever.
When
PHYSICAL and LITERARY. 107
When we fee a body continuing to move
with the felf-fame velocity which is received
from the hand, is it not more natural to fay,
that it does fo for want of a power or adiivity
to flop itself, or to deftroy this motion,
than to imagine the body to be no way de¬
termined by the impulfe, but to be carried
on with an equal force by a power of its own
continually exerted after the impulfe. Such
obfequious complaifance of the ftone, in imi¬
tating fo exactly the motion of the hand,
muft appear extremely curious 3 efpecially
if we confider what a violent oppofition it is
fuppofed to have made, before it yielded to
the motion at firft. It brings to remem¬
brance the man in the parable, who faid , he
would not go, hut went : or perhaps it may be
likened to a young fellow learning to dance,
who bends his limbs but aukwardly at firft
fetdng out, till being led about for a while
in the mafter’s hand, he can afterwards con¬
tinue the ftep of himfelf. If, in the collifion
of bodies, the one body could thus adapt and
conform itfelf in all cafes to the motion of
the other 3 it feems to be the higheft in-
juftice to refufe it the power of fenfation and
cpnfcioufnefs.
From
'toS ESSAYS and OBSERVATIONS
From experience and obfervation we learn 5
that body is equally indifferent to motion and
reft. And this indifference appears to be
the natural confequence of the moft abfolute
Inactivity. Body muft exift either in the one
ftate or the other. But, fuppofmg it once ex-
Ifting in a moving ftate, the continuance of
the motion implies no activity in the body,
any more than it requires aftivity to preferve
a quiefcent body in a ftate of reft. And we
may, with equal reafon, enquire for the caufe
of the continuation of reft, as for a caufe of
the continuation of motion.
Philosophers have indeed entertained
various opinions concerning the continuation
of motion. Arijiotle endeavoured to explain
It by means of a vehicle or the circumpulfion
pf fluid matter, hereby only evading the
queftion, as the fame difficulty returned,
how the motion of this fluid continued.
And many of the moderns have imagined
reft to be the proper ftate of ina&ive matter,
to which it naturally tended 5 and have af-
cribed the continuance of motion to the con-
ftant and immediate agency of the Deity, or
of feme delegated intelligent power.
How
PHYSICAL and LITERARY. 109
How far the concurrence of the Deity is
. neceffary to the fupport of created beings in
general, is perhaps impoffible for us to de¬
termine: but, unlefs fome continual influ¬
ence of that fort be requifite, there appears
to be no occafion for any fpecial concurrence,
in order to account for the continuance of
motion. If however, it could be demon-
fixated, that body cannot continue to move
on in a {freight line, by virtue of the fir ft
impulfe ; what more rational folution will be
found, than to have recourfe to the efficiency
pf an intelligent principle? For tho1 it fhould
be granted, that the continuation of motion,
and the communication of it from one body
to another, cannot proceed from the inertia
pf matter; will it therefore follow, that every
atom of unintelligent and undefigning matter
is endued with an aftivity capable of moving
it with the greateft order and regularity, avS
well as variety and diverfity; conforming it-
felf to the motion of other atoms with which
it is connected ; and adapting itfelf often to
the will and intention of man ? Why fhould
we not rather rank this power of the preferT
vation of motion, with thofe other a&ive
powers employed upon matter, tho’ not eft
feudally
xio ESSAYS AND OBSERVATIONS
fentially belonging to it (fuch as gravity, at¬
tractions and repulfions of various kinds,
&c.) and refer them all to an intelligent caufe,
if there be herein difcovered the fame figna-
tures of thought and defign?
This leads us to another fource of objecti¬
ons againft the inactivity of matter. As the
very refiftance which matter makes to an ex¬
ternal force, and its prefervation of the mo¬
tion received, have been taken for fymptoms
of activity j we need wonder the lefs to find
an activity fufpeCted in matter from its gravi¬
tation, and thefe other inftances where mo¬
tion begins in bodies, without any vifible
caufe.
' It may be objected, £C That a {tone falls
to the ground without any external im-
pulfe, fo far as we can difcover ; and there-
fore dead matter begins motion of itfelf.”
Such manner of reafoning would make fhort
work of natural philofophy, Becaufe there
are a variety of motions, changes and trans¬
formations, produced every day amongft in¬
animate bodies 5 is it ftraight way to be con¬
cluded, that thefe bodies move themfelves ?
The contrary of this appears in fo many in¬
ftances, as gives good reafon to believe it ne-
PHYSICAL and LITERARY, nt
Ver happens in any cafe. We fee for certain,
many motions begun by animated beings;
we obferve many bodies moved by the im-
pulfe of other bodies ; and the mechanical
caufes of fome motions, have through time
been difcovered, which were not formerly
perceived. Once in a day, it was found phi-
lofophy to maintain that fmoak and vapour
mounted upwards of themfelves by a princi¬
ple of levity, tho’ now one might as well af-
fert that cork rifes up of itfelf in water. Ma¬
ny phenomena were explained from an ab¬
horrence of a void, which was fully as rea-
fonable a paffion in a dead body, as the love
of a center, or an inclination to meet with o-
ther bodies. The rife of water in pumps was
afcribed to a felf-moving power in the water,
and the pulfation of the arteries to a power
they had of dilating themfelves. The power
of magnetifm bears fome refemblance to that
of gravity ; the theory of it is Rill imper¬
fect : yet there are a multitude of fads which
indicate a mecbanifm by means of fome ef¬
fluvia ; particularly the new method of ma¬
king artificial magnets by attrition, and the
•well known experiment, in which an iron
rod is preiented to a magnetic needle, the
fame
$12 ESSAYS and OBSERVATIONS
fame end being made to attract, fometimes
one pole and fometimes another, by only
changing the pofition of the rod, or invert¬
ing it up fide down; and much more by lin¬
king upon it with a hammer, or beating it a-
gainft the ground. Electricity is another
more palpable inftance of the fame fort. That
a fluid is concerned in producing the apparent
attractions and repulflons, and other more a-
fton idling effeCts of the eleCtric globe, can
hardly be doubted, however difficult it may
ft ill be to defcribe the laws to which it is fub-
jeCted in its operations. Why then ffiould it
be accounted <c whimfical” or unphilolophi-
cal to demand a caufe for the attractive power
of gravity? Tho’ all the mechanical accounts,
hitherto given of the caufe of gravity, fhould
be found unfatisfaCtory ; may it not Hill be
owing to fome unknown mechanifm, or the
intervention of matter, moving other mat¬
ter ? Or, tho’ it were fhown to be impraCtk*
cable by any mechanifm whatever, as is not
improbably the cafe; why may we not attri¬
bute it to the immediate agency of an intel¬
ligent aCtive being ?
It may be urged further by way of ob*»
jedion, “ That a power of beginning vifible
motion
PHYSICAL and LITERARY. 113
u motion is no more connected with a power
of thinking, than it is with any other pro-
perty of matter or fpirit.” This may'
poftibly be admitted in a certain fenfe, viz.
that there may, for ought we know, exiit
fome fpecies of thinking beings, deftitute of
the power of motion altogether. Oifters
have very little of it. Rut however this be, we
know, with all the certainty attainable in
phyfics, th^t many thinking beings have
fuch a power ; we fee them begin motion, a
relative motion on the ground. When that
motion is loft, they renew it and vary it again
at every ftep. They not only begin new
motion, but deftroy old motion, at pleafure i
whereas no experience can ever tell us, that
the beginning of the vifible motions of dead
matter is original and underived. And there
is this wide difference (which hath been often
remarked by authors on this fuLedt) betwixt
animated and inanimated beings, with ref-bed;
to motion, namely, that the thinking being
can determine the direction and quantity of
its motion : wrhich is a power incompatible
with dead matter ; and confequently it will
of itfelf remain for ever incapable of the Is aft
motion. Thus far therefore there is a con-
P
nexion
*i4 ESSAYS and OBSERVATIONS
\
nexion betwixt motion and thinking, that a
power of beginning motion feems neceffarily
to infer a power of thinking; tho’ we cannot
affirm inverfely, that a power of thinking
mu ft infer a power of beginning motion.
But if the bare beginning of motion feems to
require an intelligent caufe, the power of gra¬
vity, furely, has the higheft title to lay claim,
to that origin. The motions arifing from gra¬
vity are evidently of fuch a fort, as cannot,
without the greateft violence to reafon, be
afcribed to any blind tendency betwixt the
attracting bodies. This will beft appear up¬
on ftating fome of its known effects. A
ftone is drawn towards the earth in Europe
and in America ; it changes its direction in
different places, pointing always nearly to the
center of the earth, (or exactly in a line per¬
pendicular to the level furface) in the fame
manner as iron does' towards the loadftone, or
a feather to the eleCtric tube. The attractive
force of a ftone d'iminifhes, the farther it is
removed from the earth, according to a
fixed rule, or as the fquare of the diftance
encreafes. A body placed by itfelf would
move no way ; but two bodies run together.
A given body is more attracted to a large
quantity
PHYSICAL aktd LITERARY. 115
quantity of matter than to a leffer. Is it then
conceivable, that an unthinking being (bould
be endued with an adivity which it regulates
and varies in proportion to the fituation, di-
ftance, and magnitude of another body,
whilft it is fuppofed to be not in the lead in¬
fluenced or aded upon by that other body,
or any other being whatfoever ? If this {hall
be maintained, another queftion will arife.
By what adions, or what ftronger language
than this, can any man convince his neighbour
of his own reafon or underftanding ? It is pre¬
fumed, that a higher degree of evidence will
hardly be required in phyficai matters, than
what we have for the life and exigence of
one another : the voice of nature as loudly
declares the origin of gravity, that ruling
principle which binds the parts of the fyftem
together. From the circumftances obfer-
vable in the apparent mutual tendency of bo¬
dies, we are naturally led to conclude, that
gravitation is the effed of the continued
and regular operation of fome other being
upon matter ; and that bodies are either
drawn or preffed together by fomething ex¬
ternal. A power fo conftant, fo regular,
and withal fo uniformly varied and diverfi-
fied
ii 6 ESSAYS and OBSERVATIONS
fied according to different circumftances, can
proceed from nothing but an intelligent
caufe, either mediately or immediately exert¬
ed upon bodies.
When motion is obferved to begin in any
body, it mud be afcribed to one or other of
thefe four caufes; i. Some external animated
being ; 2. An external inansmated being ; 3.
A felf-moving animated faculty 3 and 4. A
felf-moving inanimate faculty. Of the for¬
mer three, there are a variety of manifeft
examples. Of the laft there can be no certain
example at all 5 and confequently we fhould
make a bad choice, in preferring it to the o-
thers : fuch a fuppofition, namely the produ¬
ction of motion from an internal inanimate
principle, is intirely without foundation *, and
feems to be much the fame thing as to allow,
that motion may begin without any caufe at all.
That fomething may begin to exift, or
ftart into being without a caufe, hath indeed
been advanced in a very ingenious and pro¬
found
PHYSICAL and LITERARY, uy
found fyftem of the fceptical philofophy*}
but hath not yet been adopted by any of the
focieties for improvement of natural know¬
ledge. Such fublime conceptions are far above
the reach of an ordinary genius ; and could
not have entered into the head of the greateft
phyfiologift on earth. The man who believes
that a perception may fubfift without a perci¬
pient mind or a perceiver, may well compre¬
hend, that an addon may be performed with¬
out any agent, or a thing produced without
any caufe of the production. And the au¬
thor of this new and wonderful dodtrine in¬
forms the world, that, when he looked into
his own mind, he could difcover nothing but
a series of fleeting perceptions ; and that from
thence he concluded, that he himfelf was
nothing but a bundle of fuch perceptions.
Mr. Baxter , in his Inquiry into the Nature
of the Human foul , and likewife in his Ma-,
tbo, endeavours to prove, that gravity cannot
be
* Ereatije on Hyman Nature , 3. vols. o&avo. This is the
fyftem at large, a work fuited only to the comprehenfion of
Adepts. An excellent compend or fummary whereof, for the
benefit of vulgar capacities, we of this nation enjoy in the
P hilojaphical EJjays , and the EJjays Moral and Political \
And to thefe may be added, as a farther help, that ufcfu!
commentary, the EJjays on Morality a?id natural Religion ,
Jig ESSAYS and observations
be a property inherent in matter ; from this
confideration, that, if body had an adtual ten¬
dency to fall down, it could not at the fame
time refill; the downward motion by its iner ia.
Which reafoning plainly fuppofes, that there
is a real aftive refinance arifmg from inertia.
And indeed, tho’ he exprefsly intends to de¬
ny the fmalleft activity in matter, yet he eve-
ry where fpeaks of as a coudtus or ten^
dency effential to matter, by which it makes
a violent oppofition to the power of gravity,
and other aftive powers. This being a que-
flion of the utmoft importance, it may not
be amifs to offer an amendment upon that ar®
gument, which will free it rrom any incon-
fiftency, and place it on its true bottom, on
which alone it can Hand its ground. To prove
then that gravity does not proceed from any
internal active force of any kind, either in the
earth or fuch bodies as fall towards it ; it is on-3
ly neceffary to affume one axiom, that no fub-
ftance can actively tend to move to two oppo-
‘ fite fides, at the fame time. It is eafy to
conceive that a body may be puffed or drawn
to oppofite fides, by two contrary external for¬
ces : in which cafe, if they are equal, the body
will remain at reftj, if unequal, it will be mo¬
ved
i
PHYSICAL and LITERARY. n9
ved to one fide, by the difference of the twa
forces. Thus, every part of a ffagnating fluid
is * prefled equally in every direction. But if
a body actively tend to one fide, it cannot a-
^lively tend to the other at the fame time 5
that being a contradiction in terms. And in
fa£t, we fhali find it impoflible, to make
two fuch efforts in our own bodies, to move
them wholly to two oppofite fides. This be-
ing granted, it follows, that if the waters of
the fea gravitate towards the earth by an a-
Ctive force, they cannot, at the fame time*
gravitate by their own activity towards the
moon, fo as to produce the tides. And there¬
fore, the gravitation in one or both cafes, is
owing to an external influence. The fame
argument, if it fhali be found conclufive*
may be applied to the attraction of the moon
towards the earth and fun, in the conjuncti¬
ons, and other fuch like cafes. The attra¬
ctions betwixt fmall corpufcles, will be fhown
to proceed from an external caufe, in the
fame manner. And hence it will follow*
that elafticity and the chymical effervefcen-
cies, are not the refult of the activity of at¬
tracting particles. And for the fame reafon,
a body thrown upwards, cannot move up by
» an
no ESSAYS and OBSERVATIONS
an active force of its own ; for that would
be oppofite to the adtive force of gravita¬
tion.
If, in order to evade the foregoing argu¬
ment, it fhould be faid, that a body never
tends to two oppofite bodies at the fame
time; but tends only to one fide with the dif¬
ference of the forces with which it would
tend to each of thefe bodies taken fepafately :
this will at leaft afford another remarkable
Inflance of that exadt regularity with which
the power of gravity is varied and adapted to
the different fituations of bodies ; and which
it is quite inconceivable that blind matter
fhould perform without the fuperintendance
of an intelligent being.
It has indeed been frequently afferted,
that bodies move towards each other by vir¬
tue of a law originally eftablifhed. But law,
that is to fay, a mere abftradt name or com-
plex notion, which is no real being, cannot
impel a ftone, and caufe it to begin to move.
Law by itfelf, with fubmiffion be it fpoken,
will avail nothing, unlefs either the fubjedts
of it have under (banding to yield a wil¬
ling obedience, or they be compelled to it
by external force.
If''
PHYSICAL and LITERARY. 121
If the firft appearances of things are to be
trufted, there is full as good reafon to affert,
that the earth draws the ftone, or the mag¬
net the iron, as that the (tone or iron move
of their own accord. Yet the fuppoiition of
one body drawing another body at a diftance,
without the intervention of other matter, is
univerfally rejected ; and that merely becaufe
of the natural impoffibility of the thing.
That a being cannot a &. where it is not, any
more than when it is not, is an axiom or
principle of reafon and common fenfe, and
not a leffon of experience. And is it not e-
qually felf-evident, that dead matter can ne¬
ver begin motion of itfelf 3 far lefs regulate
its motions according to a law? If bodies are
not fenfible of the neighbourhood of other
bodies, of their quantities of matter, and
of their precife diftance from them 5 is it to be
imagined that they will move themfelves with
fuch determined degrees of force, correfpond-
ing to the different quantities of matter and
different diftances?
The adtive powers both of attraction and
repulfion are of fuch a fort, as could not be
exercifed by the bodies themfelves, without ei¬
ther diftindt perceptions of their own fit unions
and
i.aa ESSAYS and OBSERVATIONS
and magnitudes with refpeft to other bodies,
or a regular fucceffion of fame kind of clear
perceptions, correfponding to every variety of
fituation and magnitude, and all this accompa¬
nied with a memory and a power of comparing
part with prefent perceptions. It would there¬
fore, make nothing to the prefent purpofe to
have recourfe to that extraordinary fubterfugc,
made ufe of by Mr. Hobbs on a like occafion.
That all matter is endued with an obfcure
fenfe and perception, and wants only the or¬
gans and memory of animals. And it hath
never yet been alledged, that all matter is ef-
jentially endued with a clear and diftind fen-
iation or confcioufnefs. If it fhould, we
need be at no lofs for an anfwer. For, were
that the cafe, why have we no perception of
this activity that is fuppofed to be exerted by
our own bodies in falling: to the ground ?
Dr. Clark , Wollajlon , and others, have fo
fully proved that matter is incapable of any
degree of thinking, that it is impoffible to
confute their arguments, but by fcornfully
denying the force, of all raetaphyfical demon-
ilrations whatever. If matter thinks, then
either thinking is effential to all matter, or it
arifes from the modification, magnitude, fi-
gure
PHYSICAL and LITERARY. 122
gure or motion of certain parcels of matter,
•But what can be more ridiculous than to i~
magine, that matter is as effentially con-
fcious, as it is extended ! Will it not follow*
from that fuppofition, that every piece of
matter, being made up of endlefsly feparable
parts, (that is, of parts which are as really
dlftind beings, notwithftanding their conti¬
guity, as if they had been at the greateft
diftance one from another) is made up alfo
of innumerable confcioufnefles and infinite
confufion ? And farther, if every part of
matter be felf-confcious, it would be a con-
trad idion to fuppofe that any lyftem could
he fo. The refulting fenfation or confciouf-
nefs at laft being but one diftind fenfation or
confcioufnefs, (as is that of a man) the fenfa¬
tion or confcioufnefs of every one of the
conftituent particles, would be the individual
fenfation or confcioufnefs of all and each
of the reft. In the next place, the faculty of
thinking cannot arife from the fize, figure,
texture, or motion of body: nor can be de-
ftroyed by any alteration of thefe qualities :
becaufe bodies, by any change of thefe, only
become greater or lefs, round or fquare, rare
or denfe, tranflated from one place to another,
224 ESSAYS AND OBSERVATIONS
with this or that new diredion, or velocity 3
or the like. All which ideas are quite diffe¬
rent from that of thinking 3 there can be no
relation between them.
This fort of reafoning defer ves at lead
fame dired anfwer, and is not to be over¬
thrown by any criticifm on the meaning of
the word immateriality . This, as is learned¬
ly obferved, mod certainly £C comes out to
£c be merely a negative term, comprehending
cc every thing that is not matter.” And it is not
to be doubted that if other terms, fuch as
immortality and infinity , were but examined
with the fame cc fufficient accuracy,” the one
might come out to be merely a negative
term, comprehending every thing that is not
mortal, and the other a negative term com¬
prehending every thing that is not finite.
Such premiffes as thefe are undeniably true 3
the only difficulty lies in difcerning the ufe
and importance of them. But if the rea-*
foiling fubjoined to. thefe premiffes cc be found
€C entirely conclufive,” the confequence mud
be, that, in judging of the qualities of mat¬
ter, we are in every cafe to rely upon the
report of our external fenfes, and never to
employ our reafon in comparing one thing
with
PHYSICAL and LITER ARY. 125
with another, in order to corredt our firft
imprefiions. 'Epicurus is to be applauded for
believing on the credit of his eye -fight, that
the fun and moon were no bigger than a cart¬
wheel or a cheefe. The peafant, who thinks
that the fun moves from eaft to weft every
day, is wifer in that refpedl, than the great-
eft philofopher \ and Copernicus is to be re¬
garded as a common enemy to mankind,
<c for declaring war againft our fenfes.5’
The grand queftion to be refolved in this
controveffy, is not whether we have clearer
conceptions of material or immaterial fub-
ftances, as we are equally ignorant of both ;
but whether the power of thinking, which
is a known faculty of fame fuhftance, be not
absolutely indivifible ? and as fuch, incom¬
patible with the known properties of matter ?
The moft plaufible objection that can well be
made againft this argument, arifes from the
late obfervations made concerning the poly¬
pus, and other living creatures of that kind.
Yet thefe, when duly considered, will be
found entirely conftftent with the indivisibi¬
lity and unity of thinking fuhftance. They
do indeed exhibite a remarkable peculiarity
in the manner of the propagation of thefe
animals 3
i<i6 ESSAYS and OBSERVATIONS
animals ; and perhaps give fome ground for
conjecturing, that a number of animals, or
a fyftem of thinking beings, may probably be
conjoined together, under the form of one
animal. We were formerly acquainted with
inftances of two or more animals connected
or adhering together, as in worms of differ¬
ent kinds, tho* they do not grow or extend
themfelves to any larger dimen (ions upon re¬
paration. Other animals were known, which,
upon loiing a limb, had it regenerated again,
as is the cafe of craw-fifh and lobfters. May
it not then be fuppofed, that, in the polypus,
both thefe cafes concur together ?
He who allows, that the fyftem of the u-
niverfe may proceed at prefent without any
guidance or direction, will find it difficult
to afiign to himfelf any good reafon, why it
might not always, or from eternity, have
done the fame. The excellency and perfe¬
ction of the material world, can be no evi¬
dence to him of an original architect or con¬
triver of all things : ffnce the higheft excel¬
lencies and perfections are acknowledged, e-
ven by every Theift, to exift without a caufe.
But the inftances of a wife adminiftration and
fuperintendence, prefented every moment to
our
PHYSICAL and LITERARY. 127
our view, ftrike the mind in the moft forci¬
ble manner. We are eye-witneffes of pro¬
vidence, but not of creation. The contem¬
plation of every part of nature, furnifhes us
with irrefiftible proofs of intelligence, coun-
fel and defign, ftill employed in actuating,
moving, conducing and governing the uni-
verfe. Nihil eft enim , quod rati one, et nume -
ro moveri poffit fine conjilio , in quo nihil efi te-
meranum , nihil varium , nihil fortuitum . Or-
do autem Jiderum et conjlaniia , ncque naturam
fignificat ; g/? enim plena rationis : neque for -
tunam , arnica v arietati confiantiatn re -
//av/. yav vide at, non impie folum ,
indocle faciat , fi Deos effe neget #
multnm inter efi, utrum id neget , an
eos omni procuration , add i one privet:
mihi enim , yof wL/ agit , ^ omnino non vide -
fur. Cic. de Nat. Deor. lib. II. cap. 16.
We obferve indeed, in various inftances,
a fubordination of natural caufes and effedts,
ana a dependence of one thing upon another.
To inveftigate thefe, is the proper province of
natural philofophy. The philofopher’s buhnefs
ss, to learn the confutation of things as they
really are 3 and to Larch out the laws and
order
I2S ESSAYS AND OBSERVATIONS
order eftablifhed in the material world, and
by which it is conducted. The mod fuccefs-
ful enquirers into nature, have feen moft rea-
fon to refolve all things finally, into an incor¬
poreal, intelligent, and powerful fir ft caufe:
and have rejoiced in the perfuafion, that they
themfelves, and all parts of the univerfe,
are the offspring, and under the adminiftra-
tion, of the fame great, wife, and benefi¬
cent parent. But they are not follicitous in
limiting the number of fecond caufes, far
lefs in excluding them altogether, as fome
over zealous friends to religion have done.
Plutarch in recommending the philofophy
of Anaxagoras , obferves, that fuperftition
proceeds from ignorance of caules, and want
of experience ; but that natural philofophy
banifhes all fuperftition, and begets in the
mind a well grounded piety, with comfort¬
able hopes*
Many
^ &si<rt$ou[Aovi& 7 rgo$ ret, fxsncc^ix, S'.ccyJvO; sgy&Qrott
OCVTOOV T£ TOVTM CCiTlGC; CCyVGXdi. 0 (pVdlKOq A 0-
yas T7iv K<T<p<x,\vi pzr zXtti^oov ccy&^tt]/ svreGsiotv mgyxty-
Vit. p£RICL.
PHYSICAL and LITERARY. 129
Many fruitlefs attempts have formerly
• been made to explain ail the phaenomena of
nature, on mechanical principles alone. But
it is exceedingly furprifmg, that, in the prefent
age, fo eminent an aftronomer as M. Mau~
pertuis ^ fhould again revive exploded notions 5
and fuggeft, that the planets may poffibly be
retained in their orbits, by the motion of a
circumambient fluid, as an ultimate caufe*
There is nothing more demonftrably certain,
than that gravity cannot arife from the pref-
fure of a whirlpool, or vortex of a denfe flu¬
id, once put in motion, and continuing to
move round of itfelf, as M. Des Cartes ima¬
gined. And it is needlefs at prefent to exa¬
mine, whether it can be better explained by
means of a rare elaftic aether. If Sir Ifaac
Newton endeavours in that manner to account
for gravity, the attraction of cohefion, the
reflexion and refraCtion of light, &c* it is
only with a view to point out fome more ge¬
neral mechanical caufe, upon which all thefe
powers may poffibly depend. He never could
believe that his aether was poffeffed of a real
activity of its own. The elaidicity of that
R fluid
Co/ma logic.
i%o ESSAYS AMD OBSERVATIONS
fluid, mu ft itfelf either proceed from fome
higher mechanical caufe, or flow immediate-
ly from fome vita! intelligent principle, which
muft he im mechanical. The mutual repul-
lions betwixt one particle and another of the
fluid, and betwixt the fluid and the bodies
fwimming in it, difcover as much variety and
regularity, as were before obferved in the
phenomena of gravity; and muft confequently
be regarded as the continual effeds of thought
and delign.
It feems to have been far from Sir Ifaacs
intention, to afcribe adivity to matter in any
fhape ; tho’ his meaning has been fometimes
miftaken To do fo, would be a manifeft
contradidion to the primary laws of motion.
i - *
delivered by hinlfeif in the beginning of his
Principia.
According to Spinoza, one piece of mat¬
ter is moved by another, and that by a third ;
and thus there is a progreffion of caufes and
effeds, in infinitum , all ading blindly, with¬
out intelligence and deflgn. Not to repeat
here, the metaph deal argument againft the
poffibility of an endlefs feries of dependent
caufes
® Ph'ilofophical EJJays. p. no.
PHYSICAL and LITERARY.
I3I
eaufes of any kind, it will be a fufficient
. confutation of this fcheme to obferve, that it
fuppofes that an infinite number of undefir.n-
ing beings can continually produce the greateft
order, regularity and harmony: which is no
better fen fe than to fay, that, tho’ one Angle
cypher be of no value, yet an infinite num¬
ber of nothings can amount to a real quan¬
tity. There is no other poffible method
whereby to judge of the intelligence or wif-
dom of any being, but by it’s fenfible effedts;
and we may as eafily fuppofe one fingle life—
lefs being to produce by itfelf the ordinary ef¬
fects of wifdom, as that they can re-uk from
the fucceflive adtion of an infinite number of
them.
Because the world is often compared to a
machine, it hath been imagined, that, when
once let a going, it may continue its motions
without any further interposition of the Au¬
thor of nature, or any other being. If we
attend however to any machines of huirrn
contrivance, we only learn, that all their mo¬
tions depend upon certain adtive powers, as
gravity and elafiicity. Thefe are employed
by ingenious artifts, fuch as they find them,
to many ufeful purpofes in life. But it is by
. confiuering
j3z ESSAYS and OBSERVATIONS
confidering the effects of thefe powers in ge¬
neral, and without regard to any particular
application, of them, that we muft determine
CQncerning their nature. And it hath been
already attempted to fhew, that they are all
probably derived from an adtive intelligence,
either immediately or mediately exercifed up«
on matter, A connexion manifeftly appears
amongft different parts of the fyftem of the
world; and many bodies in it, tho’ dead and
inanimated, are not only moved and agitated
themfelves, but communicate motion to each
other, according to a certain fixed and efta-
blifhed order, which is called the courfe of
nature. But there is no foundation in me¬
chanics for imagining, that a lifelefs body,
in confequence of a lav/ promulgated feme
thoufands of years ago, can move itfelf with
as much regularity and variety, as if it was
adtually endued with thought and reflexion.
This, to moil people, will appear an im-
ppffibility, as much, as to make a blind man .
to fee, whilfl he continues blind. And there
are few, but will at ieaft acknowledge the
contrary opinion to be fupported with fa
high a degree of probability, as juftly to de¬
fence
PHYSICAL and LITERARY. 133
ferve the preference. Haec quidcm , fi non ve¬
na y faltem verifimiliima videtur.
<c It is alledged, that the fyftem of the
cc world would difcover more contrivance, if
it went on of itfelf, without any concur-
<c rence of the Deity.” That Mr. Boyle
gives any countenance to this opinion, cannot
be pofitiveiy concluded from his words. Pie
does not fay, that brute matter moves itfelf^
but that £C it is managed by certain laws, and
cc upheld by God’s ordinary and general con-
cc courfe.” The lefs power is exerted to pro¬
duce a given effedt, the mec^anifm may juft-
ly indeed be efteemed the more perfedt. Rut
a machine going on without a moving power
at all, is a thing quite unheard of. And
where would be the beauty of every body3
every wheel moving itfelf, wdthout a depend¬
ence of one part upon another ? There would
then be no mechanifm at all. Let the ma¬
chine be as grand and perfedt as poiilble \ it
muft ftand in need of a firft mover, not on¬
ly to begin the motion, but to preferve it. If
every part lpontaneoufly moved itfelf, it is
then no machine ; fome other name muft
be found ior fuch an arrangement or fyftem
pf things* If all the motions and changes
of
334 ESSAYS and OBSERVATIONS
of bodies are performed immediately by the e
bodies themfelves, without the influence of
other matter, or any other power; there is
an end of all enquiries intocauies and effects;
philoSophy muft be degraded to a bare know¬
ledge of fads, a hiftory of nature.
There is an argument, in the form of a
reduStio ad. abfurdum, brought againft the re¬
ceived opinion of the equality of action and
readion, which had almoft been overlooked.
The fubftance of it is this, that as the preffure
undequaque, is a confequence of the law of
equal adion and reaction in fluids; lo the
fame fort of preffure ought to be a property
of folid bodies likewife, if the fame law be
univerfally extended to all bodies, fobds as
well as fluids. For a ready anfwer to this ob-
jedion, we need only recoiled the definition
of a fluid, as diftinguifhed from a folid body.
An undequaque preffure cannot obtain in a
folid body, unlefs the particles of it did yield
to any force exercifed upon them ; and, in
yielding, were eafily put in motion amongfl
themfelves ; or in other words, unieis the
folid body was converted into a fluid. A
parcel of dry fand may bear feme (mail re-
femblance to a fluid; its particles may be men
PHYSICAL and LITERARY. 135
ved more eafily amongft one another, than
thefe of a firm body, whofe parts are clofsiy
united by attraction : yet dill there muft be
a confiderable adhefion of the particles of
land, on account of their irregular figures,
and the inequalities on their furfaces. When
a man applies his hand to a hole in the fide *
of a veffel of water, he fu (tains a preffure
from the tendency of the particles to Hide
down and make their efcape : but, when his
hand is laid on the fide of a fand bank, there
is no fuch preffure to be felt ; becaufe the
particles are intangled together, and fup-
port one another. Thus a body laid upon a
rough inclined plain, may remain fixt, by
the refiftance from attrition alone ; whereas,
if the plain be fmooth, fome other power
becomes neceffary to hinder the defcent of
the body.
The mechanical action and reaction of
matter, or the changes with regard to moti¬
on and reff, which take place in the collifi-
ons of non-eladic bodies, have been already
confidered; and were found to be entirely
confident with the mod abfolute inertia . But
that real actions and equal oppofite reactions,
obtain in the active powers of attraction and
repulfion.
j36 ESSAYS and OBSERVATIONS
repulfion, is agreeable to perpetual experience;
and is no lefs certain, than that thefe powers
themfelves are eftablifhed in nature. We
find the loadftone attrads iron, and that iron
attrads the loadftone, with equal force ; and,
becaufe they attrad each other equally, they
remain at reft when they come into con tad.
If a mountain, by its gravity, preffed upon
the earth, and the earth did not read equal¬
ly on the mountain ; then the mountain
would neceffarily carry the earth before it, by
its preffure, with a motion accelerated in tn~
jinitum . The fame is to be faid of a ftone,
or the leaft part of the earth, as well as of
a mountain. A mutual attradion too is ob-
ferved amongft the diftant bodies of the io-
lar fyftem.
When a heavy body lies upon a table, and
confequently ads upon it with its whole
■ weight; there muft be an equal readion from
the power of cohefion of the parts of the
table, in order to fupport the burden. In
the fame manner, if the bottom of any vei-
fel fuftains the weight of a certain quantity of
fand, it muft read with a force equal to that
weight; otherways it muft break or give way.
The power of cohefion may indeed greatly
exceed
PHYSICAL and LITERARY. 137
exceed the particular weight which it hap¬
pens to counteract at any time : and the fame
table, at different times, may fupport very
different degrees of weight. Rut ftill it is
true, that the force exerted by this power
upon the body, can neither be greater nor
lefs than its weight, fince the reaction bare- '
ly fupports the body without beginning mo¬
tion in it. If this needs any illuftration, we
may furpofe a man to have a weight hanging
at his hand, w'hile at the fame time he pref-
fes that hand upwards againft any fix’d body $
the force with which the hand adheres to, or
is preffed againft the body, may be greater
01 lefs at pleafure 5 but the force employed
againft the weight, or that which diredly op-
poles and counterads it, muft exadly be e-
qua! to the weight itfelf.
The argument againft the law of adion and
reaction may be made to conclude with equal
force againft the law of gravity itfelf j and, if
it proves any thing at all, will even prove it
impoffible that all terreftriai bodies fhould be
endued with weight. Mutatis mutandis , the
reasoning proceeds thus. Admitting the law
of gravity, a fmooth level furface muft be the
confequence. And as the law is not con-
S fined
2^8 ESSAYS AND OBSERVATIONS"
fined to fluids, but is fuppofed to be an uni-
verfal law of matter ; a fmooth level furface
mud not only be the copfequence in fluids,
but in folids, equally. Here then is a fair
dilemma. We muft either acknowledge a
fmooth level furface to be always found in
land, powder, and indeed in all loofe bodies,
as well as in fluids ; or confine this law of
gravity to fluids. Can we remain a moment
in doubt betwixt thefe two oppofites ? we
are certain that a fmooth level furface is not
a necefiary property of folids. The gravity
of a whole hill of fand, is but an alTertion
without evidence. What remains then, but
that we adhere to the former, and reject the
latter, except as to fluids ? And thus our
author luckily, tho’ without intention, has
furnifhed a very convincing argument againfl:
the univerfality of this fuppofed law of gravi¬
tation. If a fmooth level furface is an effedt
of this law, it follows clearly, that this law
takes not place in folids, at leaf! not univer-
fally, as in fluids.
It hath been judged a fubjecft worthy cc to
tc be regreted that natural philofophers and
6£ mathematicians are not always well flailed
6£ in logics.5' A fair comparifon alone can
fhow*
PHYSICAL and LITERARY, 139
fhow, whether they be more obnoxious to
this cenfure than other people, and who are
the moft guilty of fallacious reafoning, and in
particular of that fpecies of it commonly cal¬
led Ignorantia Elenchi or Ingotyl It mu ft
indeed be avowed, that few of the mathe¬
matical philofophers have teftified any high
admiration of thofe fpacious openings and en¬
largements lately ftruck out by certain bold
and enterprizing undertakers in the dialectic
art. Nor can it reafonably be expe&ed that
they fhould entertain the moft favourable o-
pinion of fuch performances. Men who
puzzle themfelves with felf-evident axioms,
and ftumble at the plained: demonftrations*
raife a fhrewrd fufpicion that they may be li¬
able to like human infirmities in other mat¬
ters, and can have no pretentions to be recei¬
ved as infallible guides. The fartheft that
complaifance can go, is to transfer the com¬
pliment, and to regrete, that thefe univer -
fal philofophers are not always well {killed in
the elements of mathematics and natural
philofophy. * If their end in view be really
the
* MefT. Hobbs , Poland and Collins 9 have made little other
ufeofthe mathematical philofophy, than as a touch done for
difcovering their own metal. Witnefs Elementa Phyficae , Let¬
ters to Serena , and Reflexions on Mr. Clarke s fecond defence. p.$6
j4o ESSAYS AND OBSERVATIONS
the inveftigation of truth, as it is to be wi fil¬
ed ; a little more converfation and familiari-
ty with Euclid and other geometricians, might
be of good fervice to them, by aecuftoming
their minds to the fteady purfuit of real
knowledge : but if their higheft aim in life
be vain difputation, and an ofientatious dis¬
play of their abilities, in attempting to in¬
volve the cleared: truths in doubt and uncer¬
tainty, better were it for them to throw away
the rule and compafs altogether, and to ex-
ercife their faculties on other fubjeds, where
there may be more room for fubtile evafions,
and where miftakes, tho’ equally remote
from truth, and perhaps of more pernici¬
ous confequence to mankind, cannot, from
the nature of the thing, be fo eafily detect¬
ed.
Art.
PHYSICAL and LITERARY. 141
Art. III.
Pappi Alexandrini colleBiomim mathematica-
rum libri quarti propojiiio quarto, genera
H or faSia, cui propojitiones aliquot eodem
fpetfantes adjiciuntur 5 auclore Mattheo
Stewart, m Academia Edinenji Mathefeof
ProJeJJore,
PROP. IV. Lib. 4. ColleSt, Math.
Pappi Alexandria.
Sit \Tab. 1 Fig. i.J circulus ABC,
cujus centrum E, diameter BC, et
recta linea contingens AD, quae
cum BC in pundto D conveniat.
Ducatur autem DF, et juncta AE,
producatur ad G, et FKG et GLH
jungantur. Dico KE ipfi EL ae-
qualem e(Te.
Tadtum jam fit, et ipfi KL parallel duca-
tur IIXM. Ergo MX eft aequalis XH ; du-
catur etiam a punfto £ ad FH perpendicularis
142 ESSAYS AND OBSERVATIONS
EN : aequalis igitur eft FN ipfi NH : erat
autem et MX aequalis XH : ergo NX ipfi
FM eft parallela 5 et angulus PINX aequalis
eft angulo NFM, hoc eft, angulo HAX, et
in circulo funt punfta A, N, X, FI 5 eft igitur
angulus ANH aequalis angulo AXH, videlicet
angulo AEL : et propterea in circulo funt
pun 6t a A, E, N, D ; recftus eft enim uterque
•angulorum EAD, END.
Componetur autem fic, Quoniam uterque
angulorum EAD, END eft recftus, puntfta
A, D, E, N in circulo erunt. Aequalis igitur
eft angulus AND angulo AED. Sed angulus
AED eft aequalis angulo AXH, propterea
quod parallelae funt ED, XH : ergo in circu-*
lo funt A,N,X, H puntfta : et angulus HAX
angulo HNX eft aequalis : angulus autem
FI AX aequalis eft angulo FIFM : ergo FM
ip ft. NX eft parallela ; et eft FN aequalis NH:
quare et MX ipfi XH aequalis erit ; eftque
ut XG ad GE, et ita XM ad EK, et HX ad
IE : ut igitur XM ad EK, ita HX ad LE :
ct, permutando, aequalis autem eft MX ipfi
XH : ergo et KE ipfi EL eft aequalis.
Perpendcnti autem hanc propojitionem , ejufque
pulcherrimam refolutionem et compofitionem Jlatim
rt
mihi
PHYSICAL and LITERARY. 143
mihi occurrit veram ejfe, etfi redia BC non ft
■diameter • ft vcro lifeSia fit in punSlo E, et iif-
demfere verbis quibus utitur Pappus ofenditur ,
ope jequentis Lemmatis.
L E MM A. Tab. 1. Fig. 2. 3,
Suit duae rcctae AR, CD circulo in-
lcriptae, fibi mutuo occurrentes
a
in pundto E extra circulum, et bi~
fariam fecentur rcctae AB, CD in
F, G punctis, a pundio E ducatur
EH circulum contingens in H, e-
runt puncta E, F, G, H in circulo.
Et, ilfdem manentibus, fi lit pundtum
H in circumferentia, atque puncta
E, F, G, H in circulo, con tinge t
juncta EH circulum in H.
Cas. i. Si una {Fig. 2.] redtarum AB, CD,
puta recta AB,
FH.
fit diameter ; jungantur FG,
Quoniam redta CD bifedta eft in G, et eft
F centrum circuii quoniam diameter AB bi-
fefta eft in F ; redtus erit angulus FGE ;
redtus
144 ESSAYS and OBSERVATIONS
redus autem eft angulus FHE, quoniam con-
tingit EH circulum in H, quare erit angulus
FGE aequalis angalo FHE : in circulo igi-
lur funt panda E, F, G, H.
Et, iifdem manentibus, ft fit pundum H in
eircumferentia, aque pun da E, F, G, H in
circulo, continget junda EH circulum in H.
Quoniam AB diameter bifeda eft in F, erit
F centrum circuli 5 et quoniam re da CD bi¬
feda eft in G5 redus erit angulus FGE ; eft
autem angulus FHE aeqtialis angulo FGE,
quoniam in circulo funt panda E,F,G,H 3
redus igitur eft angulus FFIE ; quare con tin-
get EH circulum in pundo H.
Cas. 2. Si neutra [Fig, 3.] redarum AB,
CD fit diameter, fit K centrum circuli, et
jungantur KF, KG, RH, FH, GH et KE.
Quoniam redae AB, CD bifedae funt in
F, G pundis, erunt anguli KFE, KGE redi*
et quoniam contingit EH circulum in II, re¬
ctus erit angu'us EHK. Quoniam redi funt
anguli KGE, KHE in circulo funt panda
E, K, G, H 3 quare erit angulus FGH aequa-
!;s angulo EKH ; et quoniam redi funt an¬
guli EFK, EHK in circulo funt panda E, F*
K, IT * quare erit angulus EFH aequalis an-
gula
PHYSICAL and LITERARY.
1 45
gulo EKH, hoc eft, angulo EGH : in circu¬
it) igitur funt punda E, F, G, IT.
Et, iifdem manentibus, ft fit pundum H
in circumferentia, atque punda E, F, G, H
in circulo, continget junda EH circulum in
H. /
Quoniam redae AB, CD bifedae funt in
F, G, et eft K centrum circuli, erunt angu-
li El K, EGK redi ; quare in circulo funt
punda E, F, G, K ; in circulo igitur funt
punda E,JF, K, G, H ; quare erit arigulus
EHK aequaiis angulo EGK ; redus autem
eft angulus EGK ; redus igitur eft angulus
EHK ; quare contingit EH circulum in H.
Propofitio Peippi alt ter enunciari potefc hoc
mo do.
P R O P» Pah, i. Fig „ i«
Sit circulus ABC et recta BC circulo
occurrcns in B, C; fitque re£la AD
circulum contingens in A, et reclae
BC occurrens in D , bifariam fece-
turBCinE, et occurrat juncta AE
T circulo
I4S ESSAYS AND OBSERVATIONS
circulo in G; per punctum D du-
catur quaevis re&a circulo occur-
rens in F, H; et GF, GH, jungan-
tur reftae BC occurrentes in K, L ;
erit EK aequalis ipli EL.
Fadum jam fit, et ipfi KL parallela duca-
tur HM redis GF, GAoccurrens in M, X;
et bifariam fecetur FH in N, et jungantur
NE, NX, NA et AH.
Quoniam eft EK aequalis ipfi EL, erit
et MX aequalis ipfi XH ; eft autem FN ae¬
qualis ipfi NH 5 parallelae igitur funt redae
NX, FM ; quare erit angulus HNX aequalis
angulo HFM, hoe eft, angulo HAX ; in eir-
culo igitur funt punda A, N, X, H : eft igitur
angulus ANH aequalis angulo AXH, hoc
eft, angulo AEL ; quare in circulo funt pun¬
da A, E, N, D ; contingit igitur AD cireu-
lum [per Lem. praec.] in A, quod quidem.
ita fe habet.
Componetur autem fic. Quoniam contin¬
git DA circulum in A, in circulo funt pun-
da A, E, N, D [per Lem. praec.] ; quare e-
rit angulus AND aequalis angulo AED, hoc
eft angulo AXH 5 in circulo igitur funt pund-
da
PHYSICAL and LI TER R Y.
*47
€ta A, N, X, H ; quare erit angulus HNX
aequalis angulo HAX, hoc eft, angulo HFM;
parallelae igitur funt reftae NX, FM ; et quo-
niam eft FN equalis ipfi Nil, erit et MX ae¬
qualis ipft XH, quare erit et EK aequalis ipft
EL. E. D.
Alias quoque propofi tones hide fpeblantes ex-
cogitavi> quarum aliquot huic Jubjicere mfum
ejl.
PROP. I. Tab. i. Fig. 4.
Sit circulus ABC, et re<5ia AB circulo
occurrens in A, B; et fit C pundtum
in circumferentia circuli ; jungan-
tur CA, CB, fitque redta DE paral-
lela redtae AC, redlis AB, CB oc¬
currens in D, E ; per pundtum D
clucatur quaevis recta circulo oc¬
currens in F, G ; et CF, CG jun-
eantur redtae DE occurrentes in
O
H, K ; erit redtangulum HEK ae-
quale redtangulo CEB.
Factum
s48 ESSAYS and OBSERVATIONS
Factum jam fit, et jungantur BH, BF?
Quoniam eft redtangulum HEK aequaie re-
dtangulo CEB, in circulo funt pundta K, H,
C, B 3 qaare erit anguius BHD aequalis an¬
gulo BCG, hoc eft, angulo BED: in circu¬
lo igitur funt pundta B, H, F, D3 aequalis igi-
tur eft anguius ADH angulo CFB, hoc eft,
angulo CAB 3 quare erit DE parallela redtae
ACe Quod quidem ita fe liabet.
Componetur autem fic. Quoniam eft re-
fta DE parallela redtae AC, erit anguius
ADH aequalis angulo CAB, hoc eft, angulo
CFB: in circulo igitur funt pun din B, H,
F, D 3 quare erit anguius BHD aequalis angu¬
lo BFD, hoc eft, • angulo BCG : in circulo
igitur funt pundta K, H, C, B3 quare erit re¬
dtangulum HEK aequaie redtangulo CEB*
Q_ E? Do
L E M M A.
Sint recdae A, B. C, D ; E,F, G, H ; Ur-
quo ut A ad B, ita C ad D, et ut E
ad F, ita G ad H ; erit reUangulum
- A iri E ad reUangulum B in F, ut
rectangulum
PHYSICAL and LITERARY. 143
rectangulum G in G ad rectangulmn
DinH. ,
it *
Efi: enim redtangulum A in E ad redtangu-
lum B in E, ut A ad B, hoc eft, ut C ad^D,
hoc eft, ut rectangulum C in G ad redtangu-
lum D in G 5 et eft redtangulum B in E ad
redtangulum B in F, ut E ad F, hoc eft, ut
G ad H, hoc eft, ut redtangulum D in G ad
redtangulum D in FI : quare, ex aequo, erit
redtangulum A in E ad redtangulum B in F,
ut redtangulum C in G ad redtangulum D in
FL Q^E. Do
P R O P. IL Fig. 5. Tab. 1.
Sit circulus ABC, et re<5fca AB circa-
lo occurrens in A, B; et fit C pun-
&.um in circumferentia circuit, et CA,
CB jungantur, et fit puii&um D in
refta AB, fitqire BE ad BC ut BD
ad DA ; per pun Pram D ducatur
quaevis redta circulo occurrens in F,
G; et CF, CG jungantur rectae AB
occiirrentes in H, K; erit rectangu-?
KC • luni
i5o ESSAYS AND OBSERVATIONS
lum HAK ad re&angulum HBK,
ut quadratum ex AC ad redlangu-
lum CBE,
Faftum jam fit, et ducatur DL parallels
reftae AC reftis CB, CF, CG occurrens in
L, M, N ; et per punftum L ducatur parallels
reftae AB reftis CF, CG occurrens in O, P.
Quoniam eft reftangulum HAK ad reftan-
gulum HBK, ut quadratum ex AC ad re¬
ftangulum CBE, erit, alternando, reftangu-
lum HAK ad quadratum ex AC, ut reftan¬
gulum HBK ad reftangulum C^iV. Quoni¬
am vero eft OL ad LM, ut HA ad AC, et
PL ad LN, ut KA ad AC ; erit [per Lem.
praec.] reftangulum OLP ad reftangulum
MLN, ut reftangulum HAK ad quadratum
ex AC, hoc eft, ut reftangulum HBK ad re¬
ftangulum CBE ; et, invertendo, erit reftan-
gulum MLN ad reftangulum OLP, ut re¬
ftangulum CBE ad reftangulum HBK; eft
autem reftangulum OLP ad quadratum ex
CL, ut reftangulum HBK ad quadratum ex
BC ; quare erit reftangulum MLN ad qua¬
dratum ex CL, ut reftangulum CBE ad qua¬
dratum ex BC, hoc eft, ut Be, ad BC ; et
quoniam eft BE ad BC, ut BD aa DA, hoc
PHYSICAL and LITERARY.
1 53
eft, ut EL ad LC, hoc eft, ut redangulum
CLB ad quadratum ex CL ; erit redangu-
lum MLN ad quadratum ex CL, ut redan-
gulum CLB ad quadratum ex CL : eft igitur
redangulum MLN aequale redangulo CLB.
Quod quidem [per Prop . praec.] ita fe habet,
Componetur autem fie. Quoniam eft re-
dangulum MLN, aequale redangulo CLB,
erit redangulum MLN ad quadratum ex
CL, ut redangulum C.LB, ad quadratum ex
CL, hoc eft, ut BL ad LC ; et quoniam eft:
BL ad LC, ut BD ad DA, hoc eft, ut BE
ad BC, hoc eft, ut redangulum CBE ad
quadratum ex BC, erit redangulum MLN
ad quadratum ex CL, ut redangulum CBE
ad quadratum ex BC : eft autem quadratum
ex CL ad redangulum OLP, ut quadratum
ex BC ad redangulum HBK ; quare erit re¬
dangulum MLN ad redangulum OLP, ut
redangulum CBE ad redangulum HBK ; et,
invertendo, erit redangulum OLP ad redan¬
gulum MLN, ut redangulum HBK ad re¬
dangulum CBE. Quoniam vero eft HA ad
AC, ut OL ad LM, et KA ad AC, ut PL ad
LN, erit [per Lem. praec.] redangulum HAK
ad quadratum ex AC, ut redangulum OLP
ad redangulum MLN, hoc eft, ut redan-
gulum
j 5 2 ESSAYS AND OBSERVATIONS
o-ulum HBK ad retdanaiulum CBE, et, al-
ternando, erit reclangulum HAK ad redan-
gulum HBK, ut quadratum ex AC ad re-
dtangulum CBE. CE E. D.
PROP. III. "Tab. i. Fig. 6.
Sit circulus ABC et recta AB circuit?
occurrens in A, B ; et fit C pundium
in eircumferentia circuit ; e i. CA, CB
jungantur, et fit pundtum D in redta
AB, fitque quaevis redta EF rectis
CA, CB occurrens in E, F ; et fit
FG ad CF, ut DB ad DA. ; per
pundtum D ducatur quaevis recta
circulo occurrens in H, K ; et CH,
CK jungantur redtae EF occur-
rentes in L, M ; erit redtangulum
LEM ad reclangulum LFM, ut
quadratum ex EC ad reclangulum
CFG.
Factum jam fit, et ducatur DN parallels
reftae AC reftis CB, CH, CK occurrens in
N,0>
PHYSICAL and LITERARY,
N, O, P; et per pundtum N ducatur parallels,
redtae EF, redtis CO, CP occurrens in Q. R3
Qooniam eft redtangulum LEM ad re¬
dtangulum LFM, ut quadratum ex EC ad
redtangulum CFG, erit redtangulum LEM
ad quadratum ex EC, ut redtangulum
LFM ad redtangulum CFG. Quoniam
vero eft QN ad NO ut LE ad EC, et RN
ad NP ut ME ad EC ; erit [per Lem. ad
Prop. 2,1 redtangulum QNR ad redtangulum
ONP, ut redtangulum LEM ad quadratum
ex EC, hoc eft, ut redtangulum LFM ad
redtangulum CFG : et, invertendo, erit re¬
dtangulum ONP ad redtangulum QNR, ut
redtangulum CFG ad redtangulum LFM: eft
aufem redlangiilum QNR ad quadratum ex
CN, ut redtangulum LFM ad quadratum ex
CF ; quare erit redtangulum ONP ad qua¬
dratum ex CN, ut redtangulum CFG ad qua¬
dratum ex CF, hoc eft, ut FG ad CF : et
quoniam eft FG ad CF ut DB ad DA, hoc
eft, ut BN ad NC, hoc eft., ut redtangulum
CNB ad quadratum ex CN ; erit redtangu¬
lum ONP ad quadratum ex CN, ut redtan¬
gulum CNB ad quadratum ex CN : eft igi-
tur redtangulum ONP aequale redtangulo
CNB. Quod quidem [per Prop . i.J ita fc
habet* U Componetur
I
i £4 ESSAYS and OBSERVATIONS
t
Componetur autem fie. Quoniam eft re¬
danguium ONP aequale redangulo CNBy
erit redanguium ONP ad quadratum ex CN,
ot redanguium CNB ad quadratum ex CN,
hoc eft, ut BN ad NC : et quoniam eft BN
ad NC ut BD ad DA, hoc eft, ut GF ad
FC, hoc eft, et redanguium CFG ad qua¬
dratum ex CF ; erit redanguium ONP ad
quadratum ex CN ut redanguium CFG ad
quadratum ex CF : eft autem quadratum ex
CN ad redanguium QNR, ut quadratum ex
CF ad redanguium LFM ; quare erit redan¬
guium ONP ad redanguium QNR, ut re¬
danguium CFG ad redanguium LFM : et,
invertendo, erit redanguium QNR ad re¬
danguium ONP, ut redanguium LFM ad
redanguium CFG. Quoniam vero eft LE ad
EC ut QN ad NO, et ME ad EC ut RN ad
NP ; erit [per Lem. ad Prop. 2.] redangu-
lum LEM ad quadratum ex EC, ut redan-
gulum QNR ad redanguium ONP, hoc eft,
ut redanguium LFM ad redanguium CFG :
et, alternando, erit redanguium LEM ad re¬
danguium LFM, ut quadratum ex EC ad
redanguium CFG. Q^E. D.
Corollarium*
I
PHYSICAL and LITERRY. 155
Corrolarium. Sit circulus ABC (Tab. 1.
Fig. 6.) et redta AB circulo occurrens in A,
B3 et fit C pundtum in circumferentia cireuli,
et CA, CB jungantur; fitque redta EF redtis
CA, CB occurrens in E, F; in AB produdbi
fumatur pundtum D, ut fit DB ad Dx4, ut
quadratum ex CE ad quadratum ex CF; bi-
fariam fecetur EF in T, et per pundtum D
ducatur quaevis redta circulo occurrens in H,
K, et CH, CK jungantur redtae EF occurren-
tes in L, M3 erit LT aequalis ipfi TM.
Sit FG ad FC ut DB ad DA. Quoniam
eft redtangulum CFG ad quadratum ex CF,
utFGadFC, hoc eft, utDBadDA; et eft
DB ad DA ut quadratum ex CE ad quadra-
:um ex CF : erit redtangulum Ch G ad quadra¬
tum ex CF ut quadratum ex CE ad quadra¬
tum ex CF : eft igitur quadratum ex CE ae-
quale redtangulo CFG 3 eft autem [per P?*op.
praec.] redtangulum LEM ad redtangulum.
LFM ut quadratum ex CE ad redtangulum
CFG 3 quare erit redtangulum LEM aequa-
le redtangulo LFM : erit igitur EL ad LF ut
FM ad ME, et, componendo, erit EF ad FL
ut EF ad EM 3 aequalis igitur eft EM ipfi FL:
et quoniam eft ET aequalis ipfi TF, erit LT
aequalis ipfi TM, Q^E, D.
PROP.
jij 6 ESSAYS and OBSERVATIONS
PROP. IV. Tab. i. Fig. 7.
Sit re&a AB circulo occurrens in A,
B ; et fmt rectae AC, BC eirculum
contingentes in A, B ; et per quod-?
vis punctum D in AB ducatur DE
parallela re£tae AC, rectae BC occur¬
rens in E. Si per punctum D ducatur
quaevis redta circulo occurrens in F ,
G; et CF, CG jungantur, rectae DE
occurrentes in Id, K; erit redtangu-
lum HEK aequale quadrato ex DE,
Fadtum jam fit. Jungantur CD ; et oc-
currat recta DF re£tis AC, EC in L, M; per
M ducatur re 61 a reftis AC, DE parallela)
pccurratque reftis CH, CE, CD, et AD, in
N, O, P et pundtis.
Quoniam eft redlangulum HEK aequale
quadrato ex DE, et eft reGangulum NMO
ad quadratum ex MP ut reGangulum HEK
gd quadratum exDE) erit reGangulum NMO
aequale quadrato ex MP: et eft reGangulum
FMG'
(t ' -w *• -S
PHYSICAL and LITERARY. 157
FMG aequale quadrato ex MB ; quare erit
reGangulum FMG ad reGangulum NMO, ut
quadratum ex MB ad quadratum ex MP: et
quoniam eft FL ad LC ut FM ad MN, et
GL ad LC ut GM ad MO; erit [per Lem. ad
prop. 2.] reGangulum FLG, hoc eft, qua¬
dratum ex AL, ad quadratum ex LC, ut re-
Gan gul uni FMG ad reGangulum NMO, hoc
eft, ut quadratum ex MB ad quadratum ex
MP : eft autem quadratum ex MQ^ad qua¬
dratum ex MP, ut quadratum ex AL ad qua¬
dratum ex LC, hoc eft, ut quadratum ex MB
ad quadratum ex MP ; quare erit MQaequa-
lis reGae MB: eft autem AC ad CB, ut MQ _
ad MB; aequalis igitur eft reGa AC reGae CB.
Quod quidem verum eft, quoniam reGae AC,
BC circulum contingunt in A, B punGis.
Componetur autem lie. Quoniam reGae AC,
BC circulum contingunt in A, B punGis, e-
rit reGa AC aequalis reGae BC : et eft MQ
ad MB ut AC ad CB; quare erit MQ^ aequa¬
lis reGae MB; eft igitur quadratum ex MQae-
quale quadrato ex MB, hoc eft reGangulo
FMG; quare erit reGangulum FMG ad re-
Gangulum NMO ut quadratum ex MQjid
reGangulum NMO: et quoniam eft FL ad
LC ut FM ad MN, et GL ad LC ut GM ad
MO;
?58 ESSAYS and OBSERVATIONS
MO; erit reftangulum FLG, hoc eft, qua¬
dratum ex AL ad quadratum ex LC ut re-
dtangulum FMG ad rettangulum NMO, hoc
eft, ut quadratum ex MQ^ ad reftangulum
NMO: eft autem quadratum ex MQjid qua¬
dratum ex MP ut quadratum ex AL ad qua¬
dratum ex LC, hoc eft, ut quadratum ex MQ^
ad redtangulum NMO; aequale igitureft re^>
Qangulum NMO quadrato ex MP : et quo-
niam eft reclangulum HEK ad quadratum ex
DE ut redtanguium NMO ad quadratum ex
MP, erit redtangulum HEK aequale quadra¬
to ex DE. E. D.
PROP. V. Tab. i. Fig. 8.
»
Bit recta AB circulo occurrens in A,
B, et lint rectae AC, BC circulum
contingentes in A, B; per pundtum
quod vis D in AB ducatur re£ta cir¬
culo occurrens in F, G; et CF, CG
jungantur, redtae AB occurrentes in
H, K ; erit reclangulum HAK ad
reclangulum HBK, ut quadratum
ex AD ad quadratum ex DB.
Fadtum
PHYSICAL and LITERARY. i59
Fadum jam fit. Et ducatur DL parallela
r’edae AC, redis CB, CF, CG occurrens in
L, M, N; et ducatur LO parallela redae AB,
redlis CF, CG occurrens in O, P.
Quoniam eft redangulum HAK ad redan-
gulum HBK, ut quadraturn ex AD ad qua-
dratum ex DB, hoc eft, ut quadraturn ex
CL ad quadraturn ex LB ; et efi: redangu¬
lum IT B f v ad redangulum GLP, ut quadra-
turn ex CB ad quadraturn ex CL ; ent re¬
dangulum HAK ad redangulum OLP, ut
quadraturn ex CB vel AC ad quadraturn ex
BL: et, alternando, erit redangulum HAK
ad quadraturn ex AC, ut redangulum OLP
ad quadraturn ex BL. Rurfus, quoniam eft
OL ad LM ut El A ad AC, et PL ad LN ut
KA ad AC; erit [Lem. ad prop. 2.] redan¬
gulum OLP ad redangulum MLN, ut re¬
dangulum EIAK ad quadraturn ex AC, hoc
eft, ut redangulum OLP ad quadraturn ex
BL. Eft igitur redangulum MLN aequale
quadiato ex BL, hoc eft, quadrato ex DL.
Quod quidem [Prop, praec.] verum eft.
Componetur autem fic. Quoniam eft re-
ftangulum MLN aequale [Prep, praec.] qua¬
drato ex DL, hoc eft, quadrato ex BL,
erit redangulum OLP ad redangulum MLN
ut
360 ESSAYS a d OBSERVATIONS
ut redan gulum OLP ad quadratum ex BL 2
quoniam vero eft HA ad AC ut OL ad LivI,
et K A ad AC ut PL ad LN ; erit redangulum
[per Lem. ad prop. 2.] HAK ad quadratum
ex AC, ut redangulum OLP ad redangu-
lam MLN, hoc eft, ut redangulum OLP
ad quadratum ex BL : et alternando, erit
dangulum HAK ad redangulum OLi , ut
quadratum ex AC vel BC ad quadratum ex
BL : eft autem redan gulum OLP ad re dan -
gulum HBK, ut quadratum ex CL au qua¬
dratum ex CB 5 quare erit redangulum HAK
ad redangulum HBK, ut quadratum ex CL
ad quadratum ex BL, hoc eft, ut quadratum
ex AD ad quadratum ex DB. QHE. D*
P Pv O P. VL Tab. 1. Fig. 9.
Sint dime reftae AC, BC, circulurrt
contingentes in A, B, et fit D pun-
ctura in recta AB; fit recta EF, re¬
als AC, BC occurrens in E, F, et
junUa CD in G : fi per punttum D
ducatur quaevis recta circulo occur¬
rens in H, K, et CR, CK jungen-
tur, re£iae EF occurrences in L, M-j
PHYSICAL and LITERARY. i6i
erit: reciangulum LEM ad redtangii-
lam LFM, ut quadratum ex GE
ad quadratum ex GF0
Factum jam fit. Per pundum D ducatur
reda parallela redae AC, redis CB, CH
CK occurrens in N, O, P ; per pundum N
ducatur reda parallela redae EF, redis CH,
CK occurrens in CQ R ; et per pundum F
ducatur FS parallela redae AC, redae CD
occurrens in S.
Quoniam eft redangulum LEM ad redan-
gulum LFM, ut quadratum ex EC ad qua¬
dratum ex FG, hoc eft, ut quadratum ex
EC ad quadratum ex FS ; erit, aiternando,
redangulum LEM ad quadratum ex EC, ut
redangulum LFM ad quadratum ex FS: quo¬
niam eft redangulum QJNR ad quadratum
ex CN, ut redangulum LFM ad quadratum
ex CF, et eft quadratum ex CN ad quadra¬
tum ex ND, ut quadratum ex CF, ad qua¬
dratum ex FS; erit redangulum QNR ad
quadratum ex ND, ut redangulum LFM
ad quadratum ex FS, hoc eft, ut redangu¬
lum LEM ad quadratum ex EC. Quoniam
vero eft LE ad EC ut QN ad NO, et ME
X ad
' 162 ESSAYS and OBSERVATIONS
ad EC ut RN ad NP, erit [per Lem ad prop.
2.] reftangulum LEM ad quadratum ex EC,
ut redlangulum QNR ad redtangulum ONP ;
quare erit reftangulum QNR ad re&angulum
ONP, ut redtangulum QNR ad quadratum
ex ND : eft igitur reftangulum ONP ae qua¬
le quadrato ex ND. Quod quidem [per Prop .
4.] verum eft.
Componetur autem fic. Quoniam eft re-
dtangulum ONP aequale quadrato ex ND,
erit redtangulum QJSTR ad redtangulum ONP
ut redtangulum QNR ad quadratum ex ND;
et quoniam eft LE ad EC ut QN ad NO, et
ME ad EC ut RN ad NP, erit reftangulum
LEM ad quadratum ex EC, ut recftangulum
QNR ad redtangulurn ONP, hoc eft, ut
reftangulum QNR ad quadratum ex ND.
Quoniam vero eft redtangulum QNR ad qua¬
dratum ex CN, ut reftangulum LFM ad qua¬
dratum ex CF, et eft quadratum ex CN ad
quadratum ex ND, ut quadratum ex CF ad
quadratum ex FS ; erit redtangulum QNR
ad quadratum ex ND, ut redtangulum LFM
ad quadratum ex FS; quare erit redangulum
LEM ad quadratum ex EC, ut redlangulum
LFM ad quadratum ex FS : et, alternando,
erit reftangulum LEM ad redlangulumLFM,
ut
PHYSICAL and LITERARY. 163
ut quadratum ex EC ad quadratum ex FS,
hoc eft, ut quadratum ex EG ad quadratum
ex FG. Q^E. D.
PROP. VII. Tab. 2. Fig. 10.
Sit refta AB circulo occurrens in A,
B, et in ipla lumatur pundtum C,
et ducatur CD circuio occurrens in
D, E,/ et AD, BE jungantur fibi
mutuo occurrentes in F ; ducatur
CG parallela redtae AF, redtae BF
occurrens in G : ii per pundtum C
ducatur quaevis redta circulo occur¬
rens in H, K, et FH, FK jungantur,
redtae CG occurrentes in L, M; erit
rectangulum LGM aequale quadra-
to ex CG.
Fadtum jam fit. Jungantur CF, et oc-
currat redta CH redtis AF, BF in N, O; per
pundtum O ducatur redta parallela redtae CG,
vel AF, redtis FL, I'M, FC occurrens in P,
Q, R, et redtis AB, DE in S, T.
Quoniani
1 64 ESSAYS and OBSERVATIONS
Quoniam eft redangulum LGM aequale
quadrate ex CG, et eft redangulum POQ^ad
quadratum ex OR, ut redangulum LGM ad
quadratum ex CG; erit redangulum POQ_
aequale quadrato ex OR : et eft redangulum
HOK aequale redangulo EOB ; quare erit
redangulum HOK ad redangulum POQ,
lit redangulum EOB ad quadratum ex OR :
et, quoniam eft PIN ad NF ut PIO ad OP3
et KN ad NF ut KO ad O Qj erit j per Lem 0
pd prop, 2) redangulum HNK ad quadra¬
tum ex FN, ut redangulum XTOK ad redan¬
gulum PQQ^ hoc eft, ut redangulum EOB
ad quadratum ex OR : eft autem quadratum
ex FN. ad redangulum AND, ut quadratum
ex OR ad redangulum SOT ; quare erit re¬
dangulum HNK ad redangulum AND, ut
redangulum EOB ad redangulum SOT : et
quoniam eft redangulum HNK aequale re-
dangulo AND, erit redangulum EOB ae¬
quale redangulo SOT; quare erit OB ad OS
ut QT ad OE, hoc eft, erit BG ad GC ut
GC ad GE : eft igitur angulus GEC aequalis
angulo GCB, hoc eft, angulo BAD ; quod
quidem ye rum eft, quoniam punda A,B,E,D
fppt in drculo,
Componetur
Jr . .
PHYSICAL and LITERARY. 165
Componetur autem fie. Quoniam punfia
A> B, E, D iunt in circulo, erit angulus GEC
aequalis angulo BAD, hoc eft, angulo GCB;
quare erit EG ad GC ut GC ad GE, hoc eft,
ent OB ad OS ut OT ad OE : eft igitur re-
Aangulum SOT aequale reftangulo EOB,
hoc eft, redanguloHOK; quare erit redtangu-
lumEIOK ad quadratum ex OR, ut redtangu-
lum SOT ad quadratum ex OR, hoc eft, ut
rectangulum AND, velHNK, ad quadratum
ex FN. Quoniam vero eft FIN ad NF ut
HO ad OP, et KN ad NF ut KO ad OQ,
erit redtangulum HNK ad quadratum ex FN,
ut redtangulum HOK ad re&angulum POQj
quare erit redtangulum HOK ad redtangulum
POQ ut redtangulum HOK ad quadratum
ex OR ; eft igitur redtangulum POQ^aequa-
le quadrate ex OR : et quoniam eft redtan¬
gulum LGM ad quadratum ex GC, ut re¬
dtangulum POQ^ ad quadratum ex OR, erit
redtangulum LGM aequale quadrato ex GC.
QJE. D.
PROP. VIII. rak2.Fig.1u
Sit recta AB circulo occurrens in A}
B, et in AB fumatur punctum C,
ducatur
,66 ESSAYS and OBSERVATIONS
ducatur CD circulo occurrens in D,
E, et jungantur AD, BE, fibi mu-
tuo occurrentes in F ; per pun-
dfcum C ducatur quaevis recta cir¬
culo occurrens in G, H, et FG,
FH jungantur, re£tae AB occurren-
tes in K, L; erit reftangulum KAL
ad re&angulum KBL, ut quadrature
ex AC ad quadraturn ex BC\
Fad am jam fit. Ducatur CM parrallela
redae AF, redis FB, FK,FL occurrens in M,
N, O 5 et per pundum M ducatur parallela
redae AB, redis FK, FL occurrens in P. Ch
Quoniam eft redanguium KAL ad redan-
gulum KBL, ut quadraturn ex AC ad qua-
dratum ex BC, hoc eft, ut quadraturn ex
FM ad quadraturn ex BM et eft redangu-
lum KBL ad redanguium PMQ^S ut quadra-
turn ex FB ad quadraturn ex FM ; erit re?
dangulum KAL ad redanguium PMQ^, ut
quadraturn ex FB ad quadraturn ex BM, hoc
eft, ut quadraturn ex AF ad quadraturn ex
CM : et. alternando, erit redanguium KAL
PHYSICAL and LITERARY. 167
ad quadratum ex AF, ut redtangulum PMQ
ad quadratum ex MC. Quoniam vero eft
PM ad MN ut KA ad AF, et Q_M ad MO
ut LA ad AF ; erit [per Lem. ad prop. 2.] re¬
dtangulum PMQjid redtangulum NMO, ut
redtangulum KAL ad quadratum ex AF, hoc
eft, ut redtangulum PMQjid quadratum ex
CM : eft igitur redtangulum NMO aequale
quadrato ex CM. Quod quidem [per Prop .
praec.] verum eft.
Componetur autem fie. Quoniam eft re¬
dtangulum NMO aequale quadrato ex MC,
erit redtangulum PMQad redtangulum NMO
ut redtangulum PMQ^ad quadratum ex MC ;
quoniam vero eft KA ad AF ut PM ad MN,
ct LA ad AF ut QM ad MO ; erit redtangu¬
lum KAL ad quadratum ex AF, ut redtan¬
gulum PMQjjd redtangulum NMO, hoc eft,
ut redtangulum PMQjid quadratum ex MC;
et, alternando, erit redtangulum KAL ad re¬
dtangulum PMQ^ ut quadratum ex AF ad
quadratum ex MC, hoc eft, ut quadratum
ex FB ad quadratum ex BM: et eft redtangu¬
lum PMQ^ ad redtangulum KBL, ut quadra¬
tum ex i' M ad quadratum ex FB ; quare erit
redtangulum KAL ad redtangulum KBL ut
eft
i68 ESSAYS and OBSERVATIONS
quadratum ex FM ad quadratum ex BM, hoc
eft ut quadratum ex AC ad quadratum ex BC.
E. D.
PROP. IX. Tab. 2. Fig. 12.
Sit recta AB circulo occufrens in A. B,
et in AB fumatur punctum C ; per
C ducatur redta circulo occurrens
in D,E; et AD, BE jungantur, fibi
mutuo occurrentes in puncto F ; et
fit recta GH reefs AF, BF occur¬
rens in G, H, et junbta FC in K :
fi per punftum C ducatur quaevis
recta circulo occurrens in L, M, et
FL, FM jungantur, rectae GH oc¬
currentes in N, O; erit rectangulum
OGN ad rectangulum OHN, ut
quadratum ex GK ad quadratum-
ex HK.
Fadtum jam fit. Ducatur per pundtum
C parallela redtae AF redtis FB, FL, FM oc¬
currens in P, Q^Rj et per pundtum P du-
catuf
PHYSICAL and LITERARY. 169
catur parallela redae GPI redis F.L, FM 00
currens in S, T, et ducatur HV parallela re¬
dae PC redae FC occurrens in V.
Quoniam eft redangulum OGN ad redan-
gulum OHN, ut quadratum ex GK, ad qua¬
dratum ex HK, hoc eft, ut quadratum ex
PG ad quadratum ex HV 5 erit, alternando*
redangulum OGN ad quadratum ex FG, ut
redangulum OHN ad quadratum ex HV :
quoniam eft redangulum SPT ad quadratum
ex PF, ut redangulum OHN ad quadratum
ex FIF, et eft quadratum ex PF ad quadratum
ex PC, ut quadratum ex HF ad quadratum
ex PIV <y erit redangulum SPT ad quadratum
ex PC, ut redangulum OHN ad quadratum
ex HV, hoc eft, ut redan gulum OGN ad
quadratum ex FG. Quoniam vero eft NG ad
GF ut SP ad PQ^ et OG ad GF ut TP ad
PR, erit [per Lem . ad prop. 2.] redan gulum
OGN ad quadratum ex FG, ut rectangulum
SPT ad redan gulum QPR ; quare erit re¬
dan gulum SPT ad redangulum QPR, ut
redangulum SPT ad quadratum ex PC. Eft
igitur redangulum QPR aequale quadrate ex
PC. Quod quidem [per Prop . 7.] verum eft,
Componetur autem fic. Quoniam eft re¬
dangulum QPR aequale quadrate ex PC3 erit
Y Redangulum
ESSAYS and OBSERVATIONS
redangulum SPT ad redangulum QPR, ut
redangulum SPT ad quad rat u in ex PC : et
quoniam eft NG ad PG ut SP ad PQ , et OG
ad GF ut TP ad PR, erit redangulum OGN
ad quadratum ex FG, ut reftangulum SPT
ad redangulum QPR, hoc eft, ut redangu-
lum SPT ad quadratum ex PC. Quoniam
vero eft redanguium SPT ad quadratum ex
PF, ut redangulumvOHN ad quadratum ex
HF, et eft quadratum ex FP ad quadratum
ex PC, ut quadratum ex HF ad quadratum
ex HV 3 erit redangulum SPT ad quadratum
ex PC, ut recftangulum OHN ad quadratum
ex HV : quare erit reftangulum OGN ad
quadratum ex FG, ut redangulum OHN ad
quadratum ex HV : e£, alternando, erit re-
dangulum OGN ad redangulum OHN, ut
quadratum ex FG ad quadratum ex HV, hoc
eft, ut quadratum ex GK ad quadratum ex
HK. Q^E. D,
SCHOLIU Mo .
Prcpo/itiones ante diciae in Jediionibus quoque
comas obtinento Idque reput anti fequentia ob-
fervata funt theoremata , a quibus aha etiarn
multa dednci pojjunt .
Theor.
PHYSICAL and LITERRY. 171
Theor. 1. Sint [Tab. 2. Fig. 13.] duae re~
. diae AB, CD, fedhonem conicam contingentes in
A, C; et A,C jungantur ; Jit quaevis redla,
redlis AB, CD, AC occurrens in B, D, E, et
fedlioni in F, G pundlis ; erit redlangulum BFD
ad reciangidum BGD, ut quadratum ex EF
ad quadratnm ex EG.
Theor. 2. Sit [Tab. 2. Fig. 14.] retta AB
fedlionem conicam contingens in A, et reel a CD
fedhom occurrens in C, D pundlis ; et jungan-
iur AC, AD ; occurratque quaevis redla redlis
AB, CD, AC, AD in E, F, G, H, et fedlioni
in K, L pundlis ; erit redlangulum EKF ad
rediangulum ELF, ut reciangidum GKH ad
redlangulum GLH.
Theor. 3. hi [Tab. 2. Fig. 13.] fedlione
conica infer ibantur duae redlae AB, CD; et
jungantur AC, BD; occurratque quaevis redla
redlis AB, CD, AC, BD, in E, F, G, H, et fe¬
dlioni in K, L pundlis ; erit redlangulum EKF
ad redlangulum ELF, ut redlangulum GKH ad
redlangulum GLH.
Ex hifee patet fequens theorema .
Si in fedlione conica infer ibatur quaevis fi-
gura quadrilatera^ cue us tria la era per data
pundla in redla tranfeunt ; reliquum latus , vel
ad
,72 ESSAY'S and OBSERVATIONS
ad datum punBum verget, vel parallelum erit pe¬
tit tone data.
Ut finem fact am ; theorema mum tantum
fubjiciam , obfervatione quidem baud indignum ;
et quod etiam in feBionibus conicis, paululum mu-
tatum , obtinet ; unde aha, a nullis, quod fciarn,
Jcriptoribus geometricis obfervata , deriventur,
Sit AB diameter circuit [Tab. 2. big. 16.17.]
pofitione dati, occurratque reBa CD ipfmor-
fnalis in dato punBo C ; non fit autem C cen¬
trum circuit, et datum Jit punBum D m i,Ba
CD ; fitque quadratum ex CD majus rcBangulo
ACB,/ fit punBum C intra circulum ; fi vero
extra, fit quadratum ex CD minus reBangulo
ACB ; producatur DC ad E, ut fit CE ae-
qualis ipfi CD ; dabuntur duo puvBa F , G ex¬
tra reBam DE, ut, fi ab ipfis wfieBantur reBas
EH, GH ad punBum quodvis H in circulo, reBae
DE occur rentes vn K,L, erit fumma quadratoruin
ex DK, EK ad reBanguhm DLE in rations
data.
*
/
■
/
PHYSICAL and LITERARY. 173
Art. IV.
Of the Caufe of the Variation of the Obliquity
of the Ecliptic, by Colin McLaurxn, late
Fellow of the Royal Society , and ProfeJJor of
Mathematics in the Univerf ty of Edinburgh,
Til E French aftronomers in Peru , and
Dr* Bevis at London , and others elfe-
where, have endeavoured to determine the
1
obliquity of the ecliptic with greater accu¬
racy than former aftronomers had attained to.
The refult of their obfervations makes it to
be now about 230 29^ 28"^. It had been for
fome time reckoned 230 29' 29" 3 and before
that, 230 29" 30'" ; and, by fome antient aftro¬
nomers, 19 or 20 minutes greater. Meff. Cab -
fmi and Bradley had found it to vary a little :
and this has given occalion to a notion, that
it is decreafing continually ; that there was a
time when the axis of the earth lay in the
plane of the earth’s orbit ; that it has been
gradually riling, till now it contains an angle
with this plane of 66° 30' 3 if 5 and that, in
a
174 ESSAYS AND OBSERVATIONS
a long period of time, it will become perpen¬
dicular to this plane ; when we fhall have
everywhere a continual spring throughout
the year. The Chevalier de Louville and
M. Godin pretend even to compute the pe¬
riod of this motion ; the former having gone
to Marfeitles to meafure the variation of this
obliquity from the time when Piiheas meafu-
red it at the fame place 2000 years ago ; he
found it diminifhed by 20", and thence efti-
mates the period of this motion to be above
2 millions of years. M. Godin has fince
found, that, from the year 165510 1734, it
decreafed 55", by comparing an obfervation
of old M. Cajjinis with his own ; and thence
deduces the period to be 1944000 years.
And hence fome authors have endeavoured
to explain feveralold Egyptian and Babylonijh
traditions, concerning the fun’s having rifen
twice in the weft ; and have taken occafion
to indulge themfelves in feveral {peculations,
1 have formerly feen a piece that was
printed many years ago, but never, I think,
publiftied ^ containing a fyftem and a kind
of liturgy for the Pantheifts or Spinofifts $
wherein the author warmly efpoufed this no¬
tion, concerning the variation of the obliqui¬
ty
PHYSICAL and LITERARY.
l7$
ty of the ecliptic, and endeavoured to improve
it, for fupporting his favourite principle of
equality ; imagining, that, in the compafs of
this period, the Rate and phenomena of all
places on the earth would be upon the whole
equal ; an opinion that feems to fuit the pa¬
trons of a biind and abfolute neceffity : but,
whatever be thought of this continual and
regular diminution of the angle in which the
ecliptic and equator interfed each other, it
is certain that fuch an equality would not be
the confequence of it. Places of the earth
would Rill have their peculiarities : the peo¬
ple at the equator would have their days and
nights conRantly equal, how great or fmall
foever the obliquity of the ecliptic were ; for
this is a neceffary confequence of their de-
fcribing a great circle of the earth by the di¬
urnal motion, that is always bifedted by the
boundary of light and darknefs, which is
like wife a great circle in confequence of a ne-
cefiary truth. The poles would have their
fix months day and fix months night, as now i
with this further Angularity, that, when the
axis lay in the plane of the ecliptic, the heat
mult have been far more intolerable at the
poles than is now known in any part of the
t earth5
i7G ESSAYS and OBSERVATIONS
earth, or could be known in any other
part of it, during this long period : for the
fun mud: have then continued ten days toge¬
ther within 5° degrees of the zenith of the
poles, without any intermiffion of night, or a-
batement from a leffer elevation, at which al¬
titude he never continues above 40' in the
equinoctial days at the equator ; a peculiarity
as Angular as it would have been fatal to the
polar regions. The prefent obliquity of the
ecliptic gives evidently great relief to the e-
quatoreal regions ; as by it the fun is carried
to both fides of the zenith during the year,
and is not permitted to dart conftantly per¬
pendicular rays upon them. It is to it like-
ways the more northern countries owe their
fummer and harveft; which we are told is o-
ver with them in two months, or very little
more, while the fun's almoft continued and
inceffant acftion ripens fruits which the heat
of our fun, much lefs theirs, on the 10th of
March , the equinoctial day, could never be
able to accomplifh. Thus it ferves for dimi-
nifhing, their heat at the equator where it
was ufeful to leffen it, and for increa-
fing it towards the polar regions where it
was proper to ftrengthen it. But a regular
and
PHYSICAL and LITERARY. 177
and continued variation of the obliquity of
the ecliptic would ruin fome parts of the
world, and dilWb an order well eftablifhed
in nature, without ferving the purpofe of the
Pantheifts.
I would not take up your time in ma¬
king remarks on what is brought to fupport
this dodtrine, from old fables of Egyptian or
Babylonijh priefls delivered to Herodotus , that
feem to have flown from their vanity. What
is fhewn by Dr. Shaw , in his travels, con¬
cerning the gradual riling of the furface of the
land of Egypt , from the annual fediments of
the Nile , leems to afford a much better ar¬
gument againlt their boa fled antiquity in
Egypt , than any thing can be drawn from
aflronomical obfervations, to fupport a va¬
nity fo univerfal, that we need not go very
far from home to find abfurd enough in-
fiances of it. As for what is (aid of Pitheas
and other antients, their wrong notions con¬
cerning the refractions and the imperfecti¬
on of their inftruments, render any conclu-
lions on fo nice a fubjedt, drawn from their
obfervations, dubious. We ought to fhew*
more regard to the modern obfervations
brought for this dodtrine, than to reprefent
Z fihens
i;8 ESSAYS and OBSERVATIONS
them in a level with the fables vented by
the priefts of Egypt . According to feverai
modern obfervations, the obliquity of the ec¬
liptic varies : but we are to remember, that
even the noble Tycho Brache committed an
error of 18', in drawing his meridian in his
ifland of Teraniburgum 5 and, from his errone¬
ous opinions concerning the refraction of the
atmofphere, made the mean diftance of the
moon lefs by 4 femidiameters of the earth
than it really is. It is true, Mr. GaJJim s ob-
fervation in 1655, compared with late ones9
makes it vary at the rate of 55" in 79 years.
Let us therefore fee, if a variation, fuch as
that arifes from Meff Caffini’s and Godins
obfervations, be not a confequence of prin¬
ciples already eftablifhed in the folar fyftem ;
and offer fome hints of a method by which
it may be afcertained whether this be the juft
folution of this queftion, and how, from a
proper feries of obfervations, made with great
exaCtnefs, an improvement and correction in
geography and navigation may be deduced
from this inquiry, by bringing the theory of
the earth's motion in her orbit, and particu¬
larly what relates to the declination of the
fun to greater perfection. This will be the
more
PHYSICAL and LITERARY. 179
more ufeful, that the ufual methods of ta¬
king the latitude of places by the fun’s me¬
ridian altitudes, fuppofes the tables of his de¬
clination to be perfectly juft ; whereas there
is ground to doubt of their precifenefs.
Mathematical inftruments in general^
and fuch particularly as ferve for aftronomi-
cal purpofes, have been, of late, brought to
an exadlnefs never known in former times.
Hence fome minute motions, or inequalities
of motions, in the heavens, may be difcovered,
that have hitherto efcaped the mod diligent
obfervers. They had difcovered indeed lome
motions that are very minute or flow, fuch
as the preceflion of the equinoxes ; but this
was owing to the continual increafe of the
effedls of thofe very minute motions, which,
tho’ infenfible in one revolution, become ve¬
ry manifeft in many revolutions. Motons
of this kind are eafily found, and are accu¬
rately determined, by comparing diftant ob-
fervations. But there are other minute mo¬
tions which are hard to be difcovered : thefe
which do not grow up to be fenflble in a
number of revolutions ; their effedt in one
part deftroying their eflfedt in another part
of a revolution. Of this kind is the mo¬
tion
jSo ESSAYS and OBSERVATIONS
I •
lion lately difcovered by Mr. Bradley , which,
on this account, lay fo long concealed from
aftronomers. Of the fame kind is the moti¬
on of the fixed flars, that ought to arife trom
the parallax of the earth’s orbit. And of this
kind I fufpedt the variation of the obliquity
pf the ecliptic to be.
To proceed therefore to what I take to be
the caiife of this motion, Sir ifaac Newton
has found, that the fun and planets gravitate
all towards each other mutually ; that it is
neither the fun (according to the Coper ni* -
can fyflem), nor the earth (according to Pto-
Jomy ), that is the center of the fyflem, or
fixed point ; but the center of gravity of the
whole fyflem. That the fun therefore moves
about this center : and that when Jupiter
and Saturn , the two biggeft planets, are in
the fame right line, on the fame fide of the
fun ; the center of the fun will be, almofl a
diameter of the fun, diflant from this fixed
point. Hence, tho’ we fuppofe the earth to
move always in the fame plane, the fun will
appear to have different declinations at the
time of the fold ice : and, as the obliquity of
the ecliptic is determined always from the
declination of the fun at the foiflice, it will
therefore
PHYSICAL and LITERARY. 18$
therefore appear to vary, but not in a manner
that will accrefce and produce any fenfibie
change in our ieafons ; but it will increafe
and decreafe a little within fmalj limits, and
its variation will principally depend on the
pofition of Jupiter and Saturn to the fun and
earth, and will nearly return to the fame ma¬
gnitude when thefe return to the fame pofi-
tion, with refped; to one another, and to the
foiftice. Jupiter has mo ft effect in produ¬
cing this variation ; and, if it be found to have
a connexion or dependence on his pofition
to the fun and earth, it will be an indication
that this is the true caufe of the phenome¬
non.
Was the orbit of the earth perpendicular
to the orbit of Jupiter , this variation would
be much more confiderable than it is, and
might amount to above half a degree, or a
diameter of the fun. Suppofe [Tab. 2. Fig. 1 8.]
RET to reprefent the orbit of the earth in
fuch a cafe, C the common center of gra¬
vity of the fun and Jupiter , which we may
confider as the center of the earth's orbit, be-
caufe of the minutenefs of the earth compa¬
red with thefe, T the folftitial point, PTp
the axis of the earth, IS the right line join-
i8z ESSAYS and OBSERVATIONS
ing the centers of the fun and Jupiter, which
we funpofe perpendicular to the orbit of the
earth, while the earth is in the lolftice T.
Then, if Jupiter be at I, and the fun at S ;
the angle PTS will be the complement of the
fun’s greateft declination, or of the angle
contained by the ecliptic and equator : but, if
Jupiter be at i, and the fun at J ; the angle
PT/ will be the complement of this declina¬
tion, and thefe would differ by the angle
ST J, which, (becaufe CS is nearly equal to
a femidiameter of the fun) might amount
to 32'*
But, becaufe the angle contained by the
orbits of Jupiter and the earth is fmall, the
right line CS is feen very obliquely from the
earth, and the variation of the obliquity thence
arifing is fmall. The angle CTS is nearly
to the inclination of Jupiter’s plane to the eclip¬
tic, as the femidiameter of the fun to the di-
ftance of the earth from the fun : or the angle
CTS is about of that inclination ; there¬
fore ST f, which is equal to 2CTS, may be
fomewhat more than a minute. And this
may be fufficient to account for any variation
that is yet aifcovered by aftronomers. But,
fince it may exceed one minute, it appears
PHYSICAL and LITERARY. 1 83
that it is of moment to have this theory pro-
fecuted farther and afcertained : for an error
of a minute, in a matter of fuch moment
as the declination of the fun, which is an ele¬
ment in moft queftions in aftronomy, geogra¬
phy, and navigation, is not to be defpifed ;
efpecially now when fo great exadlnefs in
thefe matters is defired, and, I believe, may
be obtained. Such a variation, however, can
have no fenfible effect on our feafons ; and
there feems to be no ground to apprehend,
that our year will degenerate into a perpe¬
tual fpring in any period of time ; which,
after all, would be far from being an advan¬
tage to us, or to the inhabitants of the earth
in general.
A R T,
$84 ESSAYS and OBSERVATIONS
A R To V*
Concerning the fudden and furprifing Changes
obferved in the Surface of JupiterV Body y
by the fame*
THERE have been mere fudden and
furprifing changes obferved Gn the
furface of Jupiter s body, than on any other
planet in the fyftem. Cafjini has obferved
feveral belts rife on his body in one hour’s
time 3 and fpots, in very different forms, are
often feen upon him. I could wifh that the
Doiition of his fatellites were well confidered
a
when thofe changes happen : for, fince Ju¬
piter has four moons, fome of which are
much nearer to him than our moon is to the
earth 3 when they are all in conjunction or
oppofition to one another, very great tides
muft be produced in the ocean there, if there'
be any 3 and there is ground to fufpedt that
thefe ludden and great changes on his fur-
face are owing to tides analogous to thofe we
call
v / n^- . IS.
03
. *•
.r
4b
*
> i
'
/
*■
> ,/ '
- j ' *
*
PHYSICAL and LITERARY. 185
call fpring tides. Farther, the velocity with
which Jupiter revolves on his axis, and the
greatnefs of his body, mu ft contribute to the
greatnefs of thele tides, and of the inunda¬
tions produced by them.
In Jupiter s fyftem, the theory of gravity
difcovers itfelf in feme particulars more ma-
nifeftiy than in any other part of the general
fyftem. Jupiter is the only body that is, to
fenfe, fpheroidical ; the axis being lefs than
the diameter of the equator by Poftibly
we may, by farther obfervations, difeoverthe
effects of the tides likewife 5 or rather may
learn, that effects already viftble and known
proceed from them.
The a&ion of the fatellites upon one an¬
other produces fome irregularities in their
motions ; and from this it is fuppofed that
their eclipfes do not anfwer accurately to the
times computed f om the tables. But there
is another fource, I believe, of their irregu¬
larities. Jupiter s figure differs confiderably
from a fphere ; and the gravitation towards
him is not inverfely as the fquare of the di-
ftance from his center. Nov/ this variation
from the regular courfe of gravity may pro¬
duce fome inequalities in their motions. And,
A a in
i S 6 ESSAYS AND OBSERVATIONS
in order to judge of thefe, I have computed
the law of gravity towards fuch a fpheroid as
Jupiter ; and will fubjoin fome theorems on
this fubjeft.
It feems fomewhat extraordinary, that
in 130 years, fince Jupiter s fatellites were
difcovered by Galileo , no eclipfe of any of
thefe fatellites by one another has been ob-
ferved. Such an eclipfe could hold but for
a fmall time : but, as it is not difficult to com¬
pute nearly the time when they ought to hap¬
pen, it would be worth while to look for
them ; fince this might contribute to render
their theory more perfect; which is of io much
ufe in afcertaining the longitudes of places.
If it be found to be a phenomenon that
paflfes over quickly, becaufe of their fwift
motions 3 it may be the more ufeful, providing
it can be feen.
No phenomenon feems more extraordi¬
nary, relating to Jupiter , than that, according
to CaJJini , fome of his fpots revolve in lefs
time than others ; the difference amounting
to 4 . This is a phenomenon, of that kind,
of which it is perhaps beft not to attempt any
explication, till the fame be confirmed by
more obfer various*
It
PHYSICAL and LITERRY. 187
It is worthy of our notice, that, from fe¬
deral phenomena, aftronomers conclude the
Satellites to revolve on their axis, in the fame
time that they revolve around their prima¬
ries ; by which means the exceeding great
tides that would be produced in them are
avoided. Thole arifing from their various di-
ftances from the primaries, in their apfldes ,
may be fufficient for agitating their waters.
The tides that would be produced in our
moon, from this circumftance alone, ought
to be confi derably greater than the tides pro¬
duced in our ocean ; and poffibly, by a care¬
ful attention to the limits of thofe black parts
of the moon which formerly were confider-
ed as feas, but, becaufe of cavities difcovered
in them, with better telefcopes, are ill i peel¬
ed by many to be only large planes, fome
decifion of this queftion might be obtained.
Water is of too great importance, in natural
operations, to fuppofe haftily any planet to
be deprived of it ; tho’ we muft alfo allow
that the variety of nature is not to be limited
by our conceptions.
Theor.
i88 PHYSICAL and LITERARY.
* ' » •
Theor. I.
The gravity towards an oblate fpheroid
in the axis produced, decreafes in a lefs
proportion than that in which the fquare of
the dihance from the center increafes : but
the gravity in the plane of the equator de¬
creafes in a higher proportion than that in
which the fquare of the dihance increafes.
The or. II.
Let b denote the femidiameter of the e*
quator, c the dihance of the focus of the ge¬
nerating elhpfe from the center, d the di¬
hance of any body from the center of the
fpheroid in the plane of the equator 3 and the
gravity at the dihance d, will be to the gra-
at the dihance b, as £2 ^ 9C 4
^ ' • x
to I + — - , &c. * * *
&c.
so h“ ’ 56 b*
A R T.
PHYSICAL and LITERARY. 189
Art. VI.
Obfervations on Thunder and Electricity , by
Ebenezer McFait M. D.
Hj^HE experiment propofedby Mr. Frank-
X liny to prove that lightning and the e-
leetrical fire are the fame, has often been re¬
peated with fuccefs both in England and a-
broad ; fo that the moil: noted ele&rical ex¬
periments have been performed by fire drawn
from the clouds.
Mr. Franklin alfo firft difcovered, that
fharp points attract and difcharge the eleftri-
cal matter mofi: copioully ; and from thence
fuppofes, that a very (harp pointed rod, fixed
to the extremity of the top 'mail of a fhip,
with a wire conduced down from the foot
of the rod round one of the fhrouds, and
over the {hip’s fide into the fea, would filent-
lv lead oft the eledrical fire, and fave the
fhip from thunder in hot countries ; and that,
by a fimilar method, buildings might be pre-
feryed.
I90 ESSAYS AND OBSERVATIONS
So ufeful a propofal deferves to be exa¬
mined : variety of experiments may give hints
for new improvements. For this reafon the
following obfervations are communicated, tho*
not fo compleat as might be wifhed, being
the refult of one trial only.
It feldom thunders in this northern clime.
In June 1752, there feemed to be fome thun¬
der at a diflance from Edinburgh 5 but, from
the beginning of July to the beginning of
OBober , we had nothing almoft but conti¬
nual rains. The lafl fummer was uncom¬
monly warm and dry ; and yet we had only
a few claps of thunder at Edinburgh , one e-
vening : and my attempts for making any of
thofe experiments were entirely unfuccefsful
till Saturdays night September 15. when we
had a very great ftorm.
I used around iron rod, two tenths of an
Inch diameter, about eleven feet long, fharp-
ened at one end ; the other end was inferted
Into a glafs-tube ; and that tube flood in a
common glafs-bottle, which I held in my
hand.
I used alio another rod about three feet
long, fharpened in like manner, at one end ;
which flood with the other end in a glafs-
tube3
igi ESSAYS and OBSERVATIONS
tube, which was ftuck in the ground. 1
began upon the Calton-hill.
The lightning and fire in the air abound¬
ed greatly ; and yet it was fome time before
any thing elfe appeared. At laft, fome rain
began to fall, and the air turned moifter ; then
fire appeared upon the extremities of each
of the rods in a fmall pretty blaze : very like
the fire which is difcharged from the point
of a fword in the dark, when the perfon that
holds it is electrified, and hands upon glafs
or rofin ; or like that which appears upon
any (harp point, when prefented to an ele¬
ctrified gun-barrel, but in greater quantity.
I touched the long rod with my finger ; but
had no fparks from it. The (hort rod was
accidentally taken out of its tube, and yet
continued to burn and blaze as formerly. In
like manner the flame continued upon the
end of the long rod, tho’ I took hold of it
any where at pleafure above the glaffes, till I
moved my hand or finger along, within a
few inches of the flame ; then it was attract¬
ed by my hand, and vanished.
I went from the Calton-hill to the Cajlle -
hill , at the other end of the town ; and, in
pafiing thro’ the ftreets, no fire appeared up-
i92 ESSAYS and OBSERVATIONS
> »•
on either of the rods : but almoft immedi¬
ately when I got clear of the houfes, upon
the open hill, the point of the longer iron
rod took lire. In the dark, I had loft the
tube belonging to the fhorter rod ; and the
point of it did not catch fire when the long¬
er one was kindled. Perhaps I did not wait
long enough for a proper trial ; for I foon
touched the flame upon the long rod with
the fharp point of the fhort one, and then
it alfo took flame and continued burning, as
before, without any further dependence up¬
on the longer one.
I held the fhorter rod by the fharp end,
and approached the blunt end of it to the
flame, upon the point of the longer rod ;
then this blunt end catched the fire, and the
flame upon the points of the two rods conti¬
nued rather ftronger, than on the Angle one
before, fo long as I kept them in contadt,
and the fires within three or four inches of
one another : but, when I drew them far¬
ther afunder, the flame upon the extremity
of the blunt rod vanifhed. This happened
as often as I tried it ; and it is evident, that
in like manner, I could have got the fire to
fix upon the points of a great many rods, and
fo.
PHYSICAL and LITERARY. i93
. fo have had them all flaming together. Once
. or twice, a flafh of lightning feemed to dart di-
reftly againfi: the point of the rod ; then the
fire, as I thought, expanded itfelf and united
with the lightning , hut it immediately began
to fhine again, when the lightning was paft.
Tho’ it rained much in time of thefe ob~
fervations, yet the fire upon the ends of the
rods did not go out until it became fo heavy.,
as if it were pouring down out of funnels.
After this I went home for fome time,
refolving to come abroad again when the
ftorm was more tolerable ; but it continued
to rain all night, fo violently, that I was
obliged, with regret, to leave feveral expe¬
riments to the chance of fome future oppor¬
tunity.
j
For example, I fufpefted that the glafs-
tubes had not been of great ufe on this oc~
cafion ; and wanted to have tried, whether I
fhould have had the fame appearances by u-
fing the rods alone, without any other ap-»
far at us. This is very probable ; as alfo, that
the glaffes, by being wet, allowed the eledtri-
cal fire to flow off as it was attracted.
1 beg leave to add a few remarks relative
to this fubjedt.
B b It
i94 ESSAYS and OBSERVATIONS
It would feem that experiments of this
kind may be made without danger, when
the thunder is at a moderate diftance.
The lightning expands itfelf, as it flies ;
and, by expanfion, lofes its vigor.
Perhaps there is one Ample and eafy way
of protecting marts and fpires from thunder,
viz. to fix horizontally, upon the higheft parts
of them, a flat round piece of wood, of a
foot diameter, or more, in order to prevent
thofe blazing fires from fixing upon them,
and accumulating.
This ftorm pafled diredly over Edin -
burgh , and came on from the fouth by weft,
as nearly as could be eftimated. There was
a great deal of lightning, that night, above
fixtv miles to the weftward : but no thunder
heard. At Glafgow , there was very much
lightning, and a few diftant faint claps of
thunder. On the road from Belford or Ber¬
wick , it lightened incefiantly ; but two claps
of thunder only were heard, and thofe very
faint : fo that there is reafon to think, that
the fire of this ftorm fpread over the breadth
of 130 miles, at leaft. I wifh I could alfo
give fome account where this thunder began,
and how far it run before it was extinguifhed.
On
PHYSICAL and LITERARY. 195
On September 3. there were a great deal
of ftreamers, which rofe nearly from the
fame point that the thunder afterwards came
from ; and gradually worked north, till they
defcended below the horizon. The air had
a thunder-like appearance, for feveral days
before this ftorm ; and for fome nights after
it, the ftreamery vapour appeared equally dif-
fufed, muddy, inert and languid, and not
vibrating any variety of colours ; as if the
more volatile parts had been confumed. It
is highly probable that lightning and the au¬
rora borealis are of the fame materials. In
hot countries ftreamers are not feen, or but
rarely ; becaufe they are kindled into thun¬
der and flafhes of lightning: in cold coun¬
tries ftreamers abound, and it feldom thun¬
ders. The ftreamers have ferved to pre¬
dict thunder to follow next day, in fummer
and they have been alfo feen to break out
into flafhes of lightning. Thunder difturbs
the motion of the magnetic needle ; and it
has been lately found in Sweden, that ftream¬
ers do the fame. Thus thunder, electri¬
city, magnetifm, and the aurora borealis ,
appear all wonderfully related 3 and many
things
ic)G ESSAYS and OBSERVATIONS
things remain undifcovered in this vaft fields
which is but juft newly opened.
As it is probable that the height which
fomephilofophers have affigned fortheftream-
ers in the atmofphere, is by feveral hundreds
pf miles too much ; it were to be wifhed
that people in various latitudes would care¬
fully obferve their altitude, at different times
of the night ; that, by comparing fi mul tan e-
ous obfervations, this matter may be deter¬
mined with more certainty.
Art.
PHYSICAL and LITERARY.
*97
Art. VII.
Some Phenomena obfervable in foggy Weather 5
by the fame.
ONE may often meet with opportunities
of making obfervations : but he may
not always have leifure enough to judge of
their importance, and make a proper ufe of
them. This is the cafe at prefent, with re-
fped: to what follows.
I have frequently obferved, in foggy wea¬
ther, during froft, that, when the fun was
come to a proper altitude, there was a bow
formed in the mift, of a white colour , and
the altitude of the bow feemed to fubtend
an angle equal to the elevation of the fun
above the horizon, and formed a femicircle.
This kind of mift comes from the ocean*
with a flow north-eafterly wind 5 and over-
fpreads all the lower grounds : but, in a
country like ours, fo much diverfified with
long ridges of hills, and interjacent plains and
valleys, one may often emerge out of the
mift
293 ESSAYS AND OBSERVATIONS
mid by g°ing UP f°me neighbouring hill ;
then he will fometimes fee the whole coun¬
try around, as it were, buried under a vaft
deluge ; and nothing but the tops of diftant
hills, appearing here and there above the
flood ; and he will think of diving down a-
gain into it, with a kind of horror. The
air at that time, in thefe regions, is very
pure, ferene, and agreeable to breathe in.
In this, or a fimilar fituation, there is a
phenomenon obfervable, which I have feen
many years ago ; namely, a rainbow formed
round one’s fhadow in the mift. The French
Gentlemen who went to Peru, with a view
to determine the figure of the earth ; having*
among many other difficulties, the emba-
raffment of tedious and very frequent fogs to
ftruggle with ; had often occafion to ob-
ferve this phenomenon. It feemed alfo worth
mentioning here, that any one who has the
curiofity may fatisfy himfelf concerning it.
I had occafion to fee it again on the 23d
of QBober laft, in travelling from Glafgow 2
northward. When I had afcended a very
little out of the fog, fo that my fhadow was
projedled amongft it ; the fun being behind,
and almoft on a level with me $ there was a
double
I
PHYSICAL and LITERARY. 19-9
double range of colours, like thofe of the
rainbow, formed round the fhadow. The
colours of the outermoft range were broad
and very diftinCt, and about two feet diftant
from the fhadow every where 3 then there
Was a darkifh interval, and after that another
narrower range of colours, clofely furround¬
ing the fhadow, which was very much con¬
tracted.
It is remarkable, that there is a ring of
light, brighter than ordinary, that furrounds
the fhadows of all bodies 3 occafioned by
the inflexion of the rays of light, as they
pafs by the furfaces of thofe bodies. But I
dure not proceed to offer my conjeflures in
what manner this inflexion of the rays con¬
tributes to the formation of thofe ranges of
colours.
Art.
200 ESSAYS AND OBSERVATIONS
A R t. VIII.
< - ' • • i
Of the Meafures of Scotland, compared with
thofe of England, by James Gray.
5 HE ftandard pint jug in the cuftody of
the burgh of Sterlings is made of brafs,
in form of a frufirum of
a cone ; it weighs near
fixteen Averdupois pounds.
It appears, by its make,
to be very old, and has
two fhields in relievo up¬
on its fide, with rude fi¬
gures upon them, as re-
pr dented in the margin.
Its dimenfions, as near as
could be taken from a
veflel of fuch rude work¬
man (hip, are, viz.
Mean
PHYSICAL and LITERARY. 201
« * ' '
Inches .
»
Mean diameter of its mouth,
Mean diameter of the bottom.
5 hr
Mean depth,
6
It was five times carefully filled with clear
river water, which was each time accurately
weighed by a nice beam, that would turn*
with lefs than a grain, when 100 ounces were
in each fcale ; and its content of water, at a
medium of thefe trials, which did differ but a
few grains from one another, was found to
Weigh 26180 troy grains.
At the fame time, a veffel which was
made to contain accurately, one hundred cu¬
bic inches, was fifed with the fame water:
and after feveral trials, which did not differ
one grain from one another ; its content in
wa"er was found to weigh 25318 troy grains.
The ftandard pint jug therefore contains
cuhic inches; and each cubic inch
of water with which the jug was filled,
weighs 253II-6 tr°y grains.
The ffandard Sterling jug, in the cuffody
of the Dean of Gild of Edinburgh , likewife
made of brafs, and weighing about 2o f A-
*, verdupois pounds, having the arms of Scot¬
land and of Sterling marked in relievo upon
C c its
202 ESSAYS and OBSERVATIONS
its fide, was in the fame manner filled with
water; and its content was found not to differ
from that in the cuftody of the burgh of
Sterlings above a fiftieth part of a cubic inch.
Perhaps it may not be improper to obferve,
that notwithftanding the nicety of the beam,
and the fmall furface of the mouth of the
veffel, which contained 100 cubic inches;
no difference was perceptible in the weight of
its content of water, tho’ the heat of this fluid
was feveral degrees both above and below
temperate in the thermometer; and that
no difference was to be found between fpring
and river water; nor even between river wa¬
ter when clear, and when fomewhat difco-
loured after a fpeat.
By a£t. pari, of 19. February 16 1 8. anent
fettling the meafures and weights of Scotland \
it is ftatute and ordained, that the wheat fir-
lot fhall contain 21^- of the Sterling jug ; and
that the bear firlot fhall contain 3 1 of the fame.
The Englijh wine gallon contains, accor¬
ding to the Guild-hall ftandard, 224 cu¬
bic inches ; but, according to ftatute, 23 1 cu¬
bic inches. The Englijh ale gallon, both
according to the Exchequer ftandard and
ftatute, contains 282 cubic inches. The Win~
chejler
PHYSICAL and LITERRY. 203
chefler bufhel, according to ad: of parliament,
1697, and ratified in the firft year of Q. Anne^
contains 2150^- cubic inches. Therefore
Cubic Inches.
The Scotch pint contains - i03tt
The Englijh wine pint, accor¬
ding to ftatute, contains - 28|-
The Englijh ale pint contains - 35^
The wheat firlot contains - 2197-^^-
The bear firlot contains - 3205-^-^
The Wincbeft ^rbufhel contains 2 1 50— 7^
According to ad pari, of 19th February
1618 above mentioned, the Scotch pint jug
►
contains, of the clear running water of Leith ,
three pounds and feven ounces of French
Froas weight, ordained to be the weight of
Scotland ; whence the Scotch pound is equal
to 7616 Froy grains, or 15^ ounces Troy.
By an accurate comparifon of ftandard
weights made at London , [yid. Philofoph.Franf-
aB. N° 470.) the Averdupois pound was found
equal to 7000 Troy grains. Therefore
The
204 ESSAYS AND OBSERVATIONS
Troy Grains •
T he Troy ounce being equal to 48o
The Scotch ounce is equal to 476
The Averdupois ounce is 43 7t
Englijh Inches .
The Scotch foot is - 12rf
The Englijh foot is - 12
The. Scotch ell, according to the
ftandard of Edinburgh, is equal
to - 37tt
The Englijh ell is - “45
The Englijh yard is - - 36
The Scotch mile contains
The Englijh mile contains
The Scotch acre
The Englijh acre contains
Englijh Feet.
5952
5280
55353tt Square.
43360 fquare*
PHYSICAL and LITERARY. 205
Art. IX.
A Differtation on the Sexes of Plants ; by
Charles Alston, M. D. King’s Botanifl
in Scotland, Fellow of the Rcyal College of
Phyficians, and ProfeJJor oj Medicine and
Botany in the Umverfty of Edinburgh.
THE fmalleft, and apparently moft defpi-
cable produ&ions of nature, are not lb
barren, but that they are capable, both to in¬
vite our fpeculations, and to recompencethem.
Even Pliny could fay, “ rerum natura nuf-
“ quam magis quam in minimis tota eft”, (a)
For how much foever the celeftial bodies de¬
clare magnificence, and immenfity of power ;
yet do they not by far afford us fo clear and
cogent arguments of wifdom and defign, as
do the bodies of animals and plants. And
for my part, fays the great Boyle, I am apt
to tnink, that the eye of a fly is a more cu¬
rious piece of workmanfhip than the body
of
(a) L» xi. 2,
*0 6 ESSAYS AND OBSERVATIONS
of the fun, at lead as far as appears to us (b).
Hence
The exquifite ftrudure of flowers, e-
fpecially of the mod minute, and fcarcely vi-
fible dud of the apices, commonly the fport
of the winds, has engaged the attention of
the learned, both of this and the preceeding
age : and yet, no body has been able to de¬
termine, with any certainty, whether it is
abfolutely neceffary to the fecundity of the
feeds, or excrementitious only ; which is the
fubjed of the following inquiry.
Animals and .vegetables reiemble one
another in fo many things, that not only fome
of the antients, but even of the moderns al¬
io, feem to be at a lofs how to didinguifh
them, or fix the limits of each of thefe king¬
doms (*:) ; yea, and to reckon analogy a dif¬
fident proof, that fuch properties as are ge¬
nerally obfervable in the one, do belong to
the other alfo. Thus Empedocles and Anaxa¬
goras feem to have reafoned, when they main¬
tained, that both fexes were conjoined in
plants; that they were animated, yea and fen-
tient
(&) Vid. Boyle’s works, fol. edit. vol. i. p. &
yol. iv. p.523.
(c) Vid. Tyrocin bot. p. 3.
PHYSICAL and LITERARY. 207
tient beings, capable of pleafure and pain,
defire and averfion, &c. ( d )
I shall follow the philofophers no fur¬
ther ; my defign being only to inquire into
the rife and progrefs of the doctrine concern¬
ing the fexes of vegetables among botanifts ;
and
[d) £t Vita et in animalibus et in plantis efle deprehenfa
efti Anaxagoras itaque et Empedocles deftderio
plantas duci aiunt ; fentire item, ac triftitia voluptateque
affici affirmant. Et Anaxagoras quidem, animalia i~
pfas effie, et voluptate ac dolore moveri, docuit ; e foliorum
fcilicet defluvio, et ex incremento, iftud colligens. Em¬
pedocles vero fexum his admiftum efte arbitratus eft. Eo»
dem modo Plato quoque appetitu folom illas duel*
“ ob vehementem fcilicet facultatis altricis neceffitatem, affir-
mabat Quod ft conftec plantas voluptate ac dolore affici,
turn .entire quoque rationi erit confentaneum : et ubi hoc
conftiterit, turn appetitu quoque duci ; ft quidem fomno
reficiuntur, et vigiliis excitantur, rationi confentaneum erit.
Ad eundem modum ft quaeramus, an fpiritum ducant, e£
fexuum miftionem habeant, an contra ftt ; multam fuper
hoc ambiguitatem, et quaeftionem prolixam excitabimus.— •
Cum in plantis reperiatur, quod unaquaeque fpecies maf-
culum genus habeat et femellum, et omnino quod mafeu-
“ lum eft afperius ac durius rigidiufque, femellum debilius
et foecundius ; quaerendum rurfus eft, inveniaturne haec
“ duo genera ftmulcommifta in plantis effe, utEMPEDOQLEs
“ dicit. Id quod ego fane ita habere non arbitror,” Thus
Aristotle de plantis, lib. i. c. i. et 2. See alfo Frag ■=■
mentum Galenj in Platonis Timaeum, c. 2. Et li-
brum de hiftoria philofophica Galeno adferiptum fub
nem.
*08 ESSAYS and OBSERVATIONS
and whether it is fupportalbe by experiments.,
or a mere hypothefis ?
Sect. I.
* Theophrastus, the greateft, as well as
the eldeft, of the Greek botaniffs whore works
have been preferved, can beft explain, why
fome plants of the fame kind were called fe¬
males, and others males, by them. I know
fome reckon Grateva more antient, and co¬
temporary to Hippocrates , on the authority ot
fome epiftles fathered on the old man, and
annexed to his works. But the learned have
proven thefe letters to be fpurious $ and that
Grateva lived not before Mithridates , whom
he complimented with the name of a plant,
as Pliny (?) informs us. As for Hippocrates
himfeif, I find in him a conyza femino , but
no other plant called either male or female.
2. But Theophraftus , who fucceeded Ari~
flotle in his fchool, in the 1 14. olympiad, ve¬
ry frequently mentions the fexes of plants.
Thus part & t iveg3 fays he, x) ruv 'opotoyem 1/, ra
r jtAEv ai/Gstv, tqc h s', &c, tx But it is faid, that
fit oi plants of the fame kind, fome flower,
“ others
(e) lib. 25. c. 6.
PHYSICAL and LITERARY. 209
a thers not ; as of the palm-trees , that the
£C male bloffoms, not the female, which a-
££ bout the fame time puts out the fruit,
££ Plants therefore of the fame kind, are thus
“ differenced, as alfo all iuch as cannot perfedi
££ the fruit.” ( / ) And elfewhere, (g) ££ the
C£ moil: common diftinftion of trees, is into
“ female and male, whereof the one is fer-
“ tile, but the other barren, in fome. Bu
££ when both are fertile, the female carries
£C the faired: fruit, un’efs fuch be called males3
“ for fo fome call them.” And aimoft all the
plants which he diftinguifhes into male and
female, are equally fertile in both fexes, as
abies, filix , cornus , tHia, cupreffus , cijlus 5
conyza , &c» Even palm-trees he divides in¬
to frudtiferous and barren 3 and the fructife¬
rous again into female and male ( h ): fo feems
not much to have regarded analogy, in the
diftinftion of fexes, except it be in one fpecies
of the palm-tree .
, D d 3« But
(f) Hift. lib. c. 22.
(£) Hift. lib. 3. c. 9,
(h) Hift. lib. %, e< S.
2io ESSAYS and OBSERVATIONS
3. But of this famous tree he fays, (/) um
lefs the fpatha be cut from the male, and,
while it retains the down, flowers and duff,
(k) be fhaken over the fruit of the female;
It will never ripen, but fall off: which this
fprinkling prevents. ££ For the male, adds
C£ he, of both the fig-tree and th t palm-tree y
£C is of ufe to the female, ^ oiov
&t r\ $s xur cZxxou TgoTTov, but in the one (7) there
£t is, quaji coitus ; in the other it happens af-
€C ter a different manner.” And elfewhere,
€£ [m) That the fruit will not continue on the
C£ female palm-tree, unlefs the flower of the
££ male with the be fhaken over it,
e£ as fome affirm, is certainly Angular : for
cc tho5 there is an evident reafon for caprifica-
e£ tion, which it fomewhat refembles; yet
££ none can be afilgned for the effedl of this
cc fptdnkling.” And leaf! it fhould hence be
Inferred in general, that female trees were
of themfelves infufficient for fructification,
without the affiflance of the males; he ob-
ferves, that in order to fuch a concluflon, this
ought
(7) Hift. lib. 2. c. 9.
[k) K ovioproc.
(/) to, Palm-tree.
(m) Cauf. Plant, lib. 3. c. 23.
PHYSICAL and LITERARY. 211
ought to appear, not in one or two inftances
. («), but in all, or the greateft part of the
females, t r,v y&g (pwiv htw Kgivopev rS ysi/S?. Of
this tree more afterwards.
4. D iosc or ides, who lived under
Nero, has a male and female mandr agora,
ahrotonum , mer curtain , anagallis , arijhlochia ,
ciftus , fUix , peeonia , polygonum , tithymalus ,
verb a [cum, and an arundo fee min a : but, without
any regard to analogy, or to their fertility or
barrenefs, does he call them fo 3 for his
curialis-mas carries the feed, and the faemhia
is barren ; and the male of all the reft, equal¬
ly fertile with the female. The fame may
be faid of Galen and the fucceeding Greeks ;
none of them, fo far as I have obferved, men¬
tioning the fexes of the palm-tree.
5. Pliny, who flourifhed under Vefpa -
Jian , fays indeed, £C Arboribus, imo potius
“ omnibus quae terra gignit, herbifque etiam,
<c utrumque fexum efle, diligentiffimi naturae
“ tradunt : nullis tamen arboribus (palma)
cc manifeftius. Mas in palmite floret, fae-
cc mina citra florem germinat tantum, fpicae
“ modo.” (0) But when he comes to mention
particular
(») As here in the fig-tree and palm-tree,
[°) L 13* c. 4*
%i% ESSAYS and OBSERVATIONS
particular plants, excepting what he has from
T ’beopkrajius of the palm-tree , he tranfgreffes
analogy as much as DioJ'corides: his mercurialis
mafculus being the feed-bearing one ; and his
other male and female plants the fame with
thofe of Theopbrajlus and Diofcorides . Hence
it appears that the palm-tree is the only in-
ftance, among the antients, where fexes are
attributed to particular plants, on account of
fertility or barrennefs : other plants being cal¬
led male or female, on various and very
different accounts, and for diftinctions fake
only*
6. In a word, from Theopbrajlus down to
Cafalpinus , who died at Rome in 1603, the
analogy between plants and animals, with
regard to fexes, feems to. have been intirely
neglefted. But Cafalpinus [p) fays exprefsly,
cc FruSum ferunt, non vero florent oxycae-
4£ drus, taxus ; in genere herbaceo mercuria-
lis, urtica, cannabis : quorum, omnium fie-
riles mares vocant, faeminas a u tern frii-
cc ftiferas. In eo tamen genere faeminas
• e melius provenire et foecundiores fieri aiunt,
p fi juxta mares ferantur ; ut in palms eft a-
nimadverfurn ;
1 I [ s l i ? i
ip) Be plantis, 1. z . c. 2,
PHYSICAL and LITERARY, 213
u nimadverfum : quafi halites quidam, ex
“ mare efflans, debilem faeminae calorem ex-
cc pleat ad frudtincandum.”
Sect. II.
7. But of late it has been maintained by
not a few, that there is as real a diverfity of
fexes in every fpecies of plants, as in every
fpecies of animals 5 and, firfl of all by the
celebrated natural!!! Dr. N. Grew , to whom
therefore the honour of the invention is
of right due. For this great man, in his
anatomy of flowers, read before the Royb¬
al Society November 9. 1676, after noticing
the fecondary ufes of the duft of the apices y
which he calls globulets or fmall particles with¬
in the the ere of the attire ; he adds, ££ But the
<c primary and chief ufe is fuch as has refpedi
<c to the plant itfelf, and fo appears to be ve-
<c ry great and neceffary ; becaufe even thofe
“ plants which have no flower or foliature,
are yet fome way or other attired ; fo
"£ that it feems to perform its fervice to the
cc feed, as the foliature to the fruit. In dif-
cc courfe hereof with our learned Savilian pro-
<£ fe.iTor, Sir Thomas Millington , he told me,
€C hs
214 ESSAYS AND OBSERVATIONS
cc he conceived that the attire doth ferve as
C£ the male for the generation of the feed.
<LC I immediately, replied, that 1 was of the
C£ fame opinion ; gave him fome reafons for
“ it, and anfwered fome objections that might
ce oppofe them.”
Whether, as fome pretend, this com¬
pliment paid to Sir 'Thomas Millington , fhows
him to have been of this opinion before our
author, I leave to the learned to determine 5
for my part, I think the words cannot bear
it. And Mr. Ray (q) gives it for Dr. Grew ,
without naming Sir Thomas .
8. Dr. Grew then proceeds to give the
fum of his thoughts concerning this matter ;
and plainly afferts, as his opinion, that when
the attire or apices break, or open, the glo¬
bules or duft fails down on the feed-cafe or
uterus , and touches it with a prolific virtue %
not by entering bodily, or as to its grofs fub-
ftance, but only by communicating to it fome
fubtle and vivific effluvia (r),
9. Among the firft who adopted this do¬
ctrine, was Mr. John Ray , that great natu¬
ral hiPcorian ; at firft indeed only as probable
(0.
{q) Hilt p. 17.
(r) See Grew’s anat. fol. p. 17s.
PHYSICAL and LITERARY. 215
CO* but afterwards as proven by many argu¬
ments, which are collected in the preface to
his jylloge Jhrpium Europearum extra Britan-
mas nafcentium , printed at London 1694, in
: whether thefe arguments fufficiently
prove the doctrine will be confidered below.
10. In 1695, Rudolphus Jacobus Camera-
rnts 5 profeiTor of botany and medicine at ‘Tu¬
bingen, publi flaed there an epijlola de fexu plan¬
tar um^ in 1 2 mo (/) : this I have not feen, but on¬
ly an ab ft rad of it in the appendix to Mifcel.
nat. cur. Dec. 3. an. 3. for 1695, an^ 1696*
by M. B. Talent ini . Here the generation of
plants to be analogous to that of animals, he
endeavours to fhew in eight particulars • the
lan of wnich lie calls the palmarium and
ponderojijjimum argumentum: and it is this, Cer-
turn eft, fays he, ad animalium generation
<c nem copulam utriufque fexus exigi : quae
in plantis adeo quoque neceftaria eft, ut ft
vel maris apices, vel faemmarum fly li, vel
utraque deficiant, nulla proles fequi poffit ;
“ ut in frumento turcico, cuijuba praemature
refecatur, et mercuriali mare, a faemina fe-
* Parata> conftat.” But then he propofes
three
(J) Vid. R. Hid. p. ig.
(0 Reprinted Francofurti,
1 ' Oi, in 4(0 Lin. bib.bot. 273*
216 ESSAYS and OBSERVATIONS
three ob'edions againft his own dodrine,
which are ftronger than all his arguments for
it ; yea, the third plainly confutes it : and
they are thefe, as Valentini delivers them ;
“ \mo, Plantae dantur apicibus copiofis, aft
« nullo ftylo praeditae; adeoque mares fine
• - faeminis, ut in equifeto, lycopodio, &c.
« 2 do Vidctur e contrario fibi obfervaflfe faemi-
“ ninum fine pretenfo virili iemine. fiio, Ader-
curialis, fpinachiae, et cannabis femelias fo-
« litario, abfque vicini maris contagio excul-
t£ tas, plurima granula feminaque foecunda
5t obtinuiffe vidit : et haec in cauia erant, cur
“ haec omnia cum aliquali oppofiti formidine
“ proponat.”
ii. In 1703, Mr. Samuel Morland laid be¬
fore the Royal Society, fome new obfervations
on the parts and ufe of the flower in plants («)}
here he fays, “ Dr. Grew falls fhort, in that
« he fuppofes the farina only to drop upon
“ the outfide of the uterus, and to impregnate
st the included feed by fome fpintuous etna *
t£ nations, or energetical imprefs.” bo he pa*
raphrafes prolific virtue and fubtle vivfic efflu¬
via. He then propofes a more probable hy¬
po thefis, as he thinks, viz. “ that th & farina
S£ is
(«) Philof, Tranfaft, No 287*
PHYSICAL and LITERARY. 217
1
€C is a congeries of feminal plants ; one of
. £C which mu ft be conveyed into every ovum
or feed, betore it can become prolific.” He
has the honour, I believe, of being the in¬
ventor of this hypothefis ; but is o far from
making it probable, that the ftrudure and po-
fition of the parts of fome of the flowers he
inftances, which are all the arguments ad¬
vanced by him for it, fufficiently confute it ;
e. g. corona imperialism For allowing for
once, which however cannot be allowed, that
the Jiylus is always hollow, and that rain,
might w^afh the duft, or wind fhake it down
this cavity, into the heart of the feed in eredt
flowrers ; what muft become of pendulous
flowers, fuch as the crown imperial ? here the
farina muft be waftied or fhaken upwards.
12. As for JValdfchmidii dijfertatio de fexu
plant arum , Kiliae 1705, 4/0, and Gakenholzii
dijfertatio de vegetal) ilium indole cognojcent!a>
Helmjladii 1706, in 4 '0, mentioned by the
learned Heijlerus , in his praejatio in epijlolam
Burckhardi ’, Helmjladii 1750, in 8 vo ; I know
nothing about them : but I have no reafon
to think, that they have been more fuccefsful
in demonftrating the lexes of plants than Ca¬
mera ri us, <c qui, omnium planillime, fexum
E e plantarum
2 1 8 ESSAYS AND OBSERVATIONS
cc plantarum expofuitf’ as the fame profeffor
Heifter (x) teftifies.
13. In 17 1 1, Mr. Gecffroy prefented the
Royal Academy at Paris , with cc obfervati-
ons on the ftrudture and ufe of the princi-
cc pal parts of flowers wherein he attempts
to prove, that the duft of the apices really
Impregnates the feed. And after advancing
a! mo ft ail that had been faid on this fubjedt
by Grew , Ray , Camerarius, Mori and, without
mentioning them ; he afferts, 1 mo, That the
arerm is never to be feen in the feed till the
O \ V
apices died their duft. And, 2 do. That, if
the /lamina be cut out before the apices open,
the feed will either not ripen, or be barren
if it ripens : in proof whereof he gives two
experiments that he made, one on the mays,
by cutting off all the jiamina before the apices
opened ; and the other on the mercurialis ,
by training up feparately fome of the feed¬
bearing plants by themfelves. The confe-
quence was, fome of the ears of the mays
aborted altogether 5 others ripened a few feeds;
as did aifo the mercurialis plants : both which
feemed to be foecund. £C Perhaps, fays he,
st the duft of the apices , brought from fome
<£ other
(at) Pref., p. 70.
PHYSICAL and LITERRY.
219
cc other place by the wind, fertilized thefe few
“ feeds : that this is not impoffible, we have
€£ a fine infiance in Jovianus Pont anus , precep-
C£ tor to Alphonfus King of Naples , who, in a
cc poem, tells us, that in his time, there were
C£ two palm-trees, a male cultivated at Brindes ,
“ and a female in the woods of Otranto , which
cc carried no fruit for many years. But at
<£ length being elevated above the other trees
cc of the forefi, fo that it could fee the male
cc palm-tree of Brundujium , it then began to
<£ bear good fruit in abundance. No doubt,
C£ becaufe then it began to receive the dufi:
€C of the /lamina , carried by the wind from
££ the male palm-tree > over the other trees of
<£ the wood (y)d A very fine ftory indeed !
I fiiall only further obferve, concerning
this learned author, that tho’ he has added
nothing new, of confequence, on this fubjedl,
yet he feems to claim the honour of being
the inventor of all ; for after giving his con¬
jectures, with relation to the manner how
th ib dufi impregnates tire teed, and as his
own too, tho’ the one be Crew’s and the o-
ther Morland' s, he thus concludes,
cc But
(y) Yid. Mem, Acad. 1711.
220 ESSAYS and OBSERVATIONS
<c But whichfoever of thefe conjedlures
ec be pitched on, it remains always certain,
C£ by my obfervations , that the dud of the a -
cc pices, which has been hitherto negleded,
C£ as vile excrements, which in a manner
C£ disfigured the flowers, are neverthelefs parts
cc effentia!, and neceflfary to the foecundity of
cc plants/’ The pains however he has been
at, in examining and defcribing the dud of
the apices , of a confiderable number of plants,
if accurately performed, might have procured
him better treatment, than he met with from
feme of his countrymen.
14. In 1717, M. Vaillant, at the opening
of the Royal garden, intertained his audience
with a difcourfe on the drudlure of flowers,
and the ufe of their parts ; which was print¬
ed in French and Latin at Leiden in 1718, in
4/0 : and thus he begins , ££ Since the flowers
££ are, without controverfy, the mod effential
££ parts of plants, it is very fit that I intertain
£C you, in the fird place, with them ; and
££ the rather becaufe every botanid hitherto,
has given only confufed ideas of them. The
££ language perhaps which I am to make ufe
of, may appear fomewhat new in botany :
?■ but, as it will abound in terms altogether
' fuitabje
PHYSICAL and LITERARY. 221
ec fuitable to the ufe of the parts which I am
cc to explain ; I believe it will be much bet-
€C ter underftood, than the old one, which
“ being fluffed with improper and equivocal
words, more apt to perplex than illuflrate
cc the matter, precipitate into error tbofe,
6£ whole clouded imagination has no right
“ notion of the functions of thefe parts. The
u flowers, ftridily fpeaking, are nothing elfe
*c but the organs which conftitute the differ-
“ ent fexes of plants, &c.5’ I fliall notice
only two or three things concerning this dif-
courfe. 17710, That, according to it, the a~
pices of barren flowers fhed their dull: all at
once, by a kind of explofion : but fertile
flowers, flowly and by degrees, and common¬
ly before they open, or expand their covers $
but he gives only the parieiaria for an in-
fiance.
2 do. That he has demonflrated that the
dull: of the apices cannot enter the feeds ; be-
caufe the ftylus is not always hollow, but of¬
ten folid : and, although it were hollow or tu¬
bular into the feed-veffel, it could not thus
convey the dud into the feeds, without pe¬
netrating their proper covers or fin ells. Be¬
sides, he afferts, and that truly too, that this
duft
%%1 ESSAYS AND OBSERVATIONS
daft does not enter even the cavity of the fruit;
as may be feen by opening the heads of the pa-
pavcr orientale hirfutijfimum flore magno, T. Cor.
p. 17. when the flower is fully blown. For,
fho’ the upper part of the heads, are then co¬
vered with the purple dufl of the apices ; yet
the feeds, partitions to which they adhere,
and all within the fruit, continue perfe&ly
white. I might add, that the dufl: of the a-
pices is fometimes in fo large grains, as to be
vifible to the naked eye : as in fome of the maU
*vaceae , while no conduits are difcoverable, by
magnifying glaffes, in the Jlylus , whofe dia¬
meter does not much exceed that of the
grains of the dufl:, which refembling prickly
balls, mu ft be very unfit to enter a ftrait paf-
fage. And,
3 tio. That the volatile fpirit, or vapour
of the dufl:, may be conveyed to the feed,
in this manner ; it may enter the air veflfels
of the jlylus , pafs through them into the
placenta , thence into the Junes umbihcales ,
and fo into the ova or feeds, along with the
nutritive juices. But I cannot omit a remark¬
able paffage in this difcourfe, as it anfwers
an afiertion of Mr. Geoffrey , and on other
accounts which take in the tranflators words,
cc Tubas
PHYSICAL and LITERARY, 22$
Tubae igitur hae, quas fallopianis compa¬
re), quod ad ova deferant, non exigua ipfa
“ ilia pulveris foecundi grana, quae apices fu-
per ilias ejaculantur, aut in ip fa rum excu-
u tiunt infundibulum, ut feftator Leeuwe n-
hoehanorum atque 11 artfoekeri anorum phan-
cc tafmatum voluit; fed halitum modo, aut
fpiritum volatilem, qui pulvere hoc fe ex^
:c pedit, ovaque ipfa foecundat. Credo eniin
:c auditores, perfuafum certumque habendum,
:t non materiam mafeulinam, nec vermiculos
:c fuppofititios, vel animalcula feminalia efie,
:c quae impregnationem in femella abfolvant:
:c quia Malpighius , narrante anatomico recen-
u te (z) agnovit foetum reperiri in ovis rana-
c rum et gallinarum ante copulam : ut et
c certiftimum eft germen adefie in feminibus
c plantarum quae non fuerunt impregnata,
c quorumque parenchyma facit cum germi-
c ne ipfo continuum corpus. Non poterit
:c ideo efle aliud quid, preter volatilem hunc
c fpiritum, cui craffior materies vehiculi mo-
c do vicem praeftat fimplicis. Natura vero
c femper eafdem fe eft ante leges, conciudere
c opportets id quod hac occafione in anima-
cc libus
{*) M. Diohis edit. 1715. p. 392,
224 ESSAYS AND OBSERVATIONS
C£ libus contingit, idem et vegetantihus acci-
« dere (a)." Upon the whole, it is evident
that Mr. Vaillant affnmes more the air of an
original writer on this (uhjedt than belongs to
him. Fie never mentions Grew , Ray, or
Carrier arias*, and quotes only fome pafleges
from Geoff roy, for the pleafure of cornu-
ting them.
15. I fhall pafs a variety of later authors
who have treated on this fubjedt ; and come
to the mod ftrenuous defender of the fexes of
plants, who has collected all the arguments
for it that perhaps can be advanced, and pre¬
tends to have demonftrated it fully : I mean
the famous and very learned Carolus Lmneus ,
profeffor of medicine and botany in the uni-
verfity of Upsal , fellow of a great many phi-
lofophical focietles ; and certainly one of the
greateft botanifts of this age. For this great
man thus writes, “ Antheras et ffigmata (b)
€C conftituere fexum plantarum, a palmicolis,
cc Millingtono , Grewio , Rayo , Carrier ario , Go -
£c dofredo , Morlando , Vaillantio , Blairio , juj*
cc ffevio, Bradley 0, Royeno , Logano , &c. de-
“ tedium;
[a) Vid. p. 57.
(b } that is, the apices, and extremity of the flylus.
PHYSICAL and LITERARY. 225
detedium, defcriptum, et pro infallibili af-
cc fumptum: nec ullum, apertis oculis confi-
cc derantem cujufcunque plantae Acres, latere
tc poteft 3 quod demonftrattum in fponfalibus
<c plant arum ^ Upfaliae 1746, in 4to (c)” And
elfewhere (d) “ Generationem v’egetabilium
“ fieri, mediante pollinis antherarum illapfu
c< fupra ftigmata nuda, quo rumpitur pollen*
“ efflatque auram feminalem , quae abforbetur
“ ab humore ftigmatis; quod confirmat ocu-
cc lus, proportio, locus, tempus, pluviae, pal-
Ci micolae, Acres nutantes, fubmerfi, fynge-
<c nefia 3 immo omnium florum genuina con-*
4c fideratio.”
Yet I cannot help thinking this doctrine
not capable of demonftration, far lefs that
the genuina conjideratio of any Aower can
make it probable : Camerarius himfelf doubt¬
ed of it 3 Tournejort difbelieved it 3 and Pon-
tedera (e) ufes many arguments to refute it*
It remains therefore only, that the argu^
mentsr for and againft the fexes of plants, as
under Aood by the moderns, efpecially the de-
F f fervedly*
(d Syftema naturae, edit. Lipfiae 1748. in 8vo, p. 216.
[cf] Philofoph. Botan. edit. Stockholm. 1751, in 8vo. p. 9s 4
{e) Anthol. 1. 2. p. 107 — 185.
226 ESSAYS AND OBSERVATIONS
fervedly much commended Carolus Linnaeus ■,
be fairly Rated .
Sect. III.
26. The Rate of the controverfy is briefly
this ; Whether the influence of the duR of
the apices , is abfolutely neceffary to the foe-
cundity of the feeds, or not : or, Whether
good and fertile feeds can be produced, when
the duR of the apices has no accefs to the Jlyli
or Jligmata of the plants that carry them.
Now, there being feveral fpecies of vege¬
tables, which bear flowers on one plant, and
feeds on another, as fpmacia , mercurialisy
cannabis , &c.; I know no way, to determine
the queflion fo certainly, as by training up
one or more of thefe feed-bearing plants,
at a fufficient diffance from fuch as carry the
flowers, and obferving the confequence:
for,
17. If a feed-bearing or female fpinacia ,
mercurialisy or cannabis , ftanding at a di¬
flance from any of the flowering or male
plants, can produce fertile feeds ; then the in¬
fluence of their duR is not neceffary to the
fertility of thefe feeds: but, cc foemellam fpi-
naciae, mercurialis, cannabis, abfque vici-
cc ni
PHYSICAL and LITERARY. 227
cc ni maris contagio excultam, femina foe-
cc cunda producere vidit Camerarius •” ergo
the duft of the apices is not neceffary to the
foecundity of all feeds. Although this tefti-
mony of Camerarius is beyond all exception 5
yet, in confirmation of it, and to prevent ca¬
villing, I fhall relate the experiments I made
with the fame plants.
1. In the Spring 1737, I tranfplanted
three fets of the common fpinage , long be¬
fore it could be known, whether they were
flowering or feed-bearing plants, from a little
bed on which they were raifed, into a place
of the garden, full 80 yards diflant, and al-
moft directly South 5 there being two haw¬
thorn and three holly hedges, all pretty thick
and tall, between them and their feed-bed $
and no other fpinage in the garden, nor fo
near them by far : all the three proved fer¬
tile plants, and ripened plenty of feeds. I
fowedthem, they grew, and profpered as well
as any fpinage feed poffibly could do. This,
I own, made me, at firft, call in queftion the
fexes of plants, which I formerly too impli¬
citly believed.
2. The fame year, a few plants of the
common hemp> which I had raifed for a fpe-
cimen
228 ESSAYS AND OBSERVATIONS
cimen from the. feed, being accidentally de-
ftroyed when very young; and finding after¬
wards, about the end of June, a pretty ftrong
but late plant of hemp* growing in the inclo-
fure to the eaft of Holyrood-houfe , commonly
called the Bowling-green, by itfelf : I caufed
great care to be taken of it ; there not being
that year any hemp raifed within a mile of it,
that I could find. This plant grew luxuri¬
antly ; and, tho’ bad weather in the Autumn
made me pluck it up a little too foon, yet I
got about thirty good feeds from it, which
the fucceeding Spring produced as thriving
male and female plants, as if the mother
hemp had flood unrounded with males. And,
3. In the Spring 1741, I carried two
young feedling plants of the French mercury ,
long before there was any in flower, from
the City Phyfic-garden, the only place where
it was then to be found in this country, to
the King's Garden at the Abbey, which are
more than 700 yards diftant from one ano¬
ther, with many high houfes, trees, hedges,
and part of a hill between them : and planted
one of them in one inclofure, where it was
ihaded from the fun the greateft part of the
day; and the other, in another, 25 yards di¬
ftant.
i • i
PHYSICAL and LITERARY. 229
Rant, expofed to the South and Weft. Both
plants ripened fertile feeds; and the laft
lhed them fo plentifully, that it proved a trou-
blefom weed for feveral years : tho’ none of
the fpecies was to be found in that garden,
for more than twenty years preceeding.
Hence the duft of the apices of thefe
three fpecies of plants, cannot, on any ac¬
count, be called their genitura. And the
fame may be faid of the lupulus , according to
Mr. Tourneforf s obfervation, (/) of the bryonia,
as noticed by Mr. Miller (g), yea of Mr. Geoff¬
rey's mays mentioned above.
18. The learned Valentini (h) attempts to
remove Gamer arius' s doubts two . ways. 1 ,
Perhaps, fays he, there may be found latent
ftyli among the apices of the equifeium ; and 2.
The wind may carry the pollen feminale, (or
duft of the apices) to as great a diftance, as
the mercurialis , vel frumenti Turcici feminina,
can be feparated from their proper males.
That the wind could have this effedt,
even on the fpinage male duft, is far from
being probable : for, to fay nothing of the
globular
(/) Page 69.
(g) Card. Di£t. abridg,
\b) German, ephemer. 1. c.
230 ESSAYS and O B S E R V AT IONS
globular figure or fpecific gravity of this
duft, a north wind only could drive it to¬
ward the females, which coming over the
Caltonhilly muft rather have driven it into the
ground, orinto the intervening hedges. Andin-
deed thisfuppofitionis fo evidently extravagant,
that I find not any notice taken of it, by the
moft ftrenuous defenders of the fexual
fcheme.
19. But the other fuppofition of the la¬
tent Jlyli , inequifeto &c. feems to have given
occafion to another as extraordinary, viz. of
latent Jiamina , in cannabis , lupuli, &c. foe-
mellis £C Accidit interdum, fays Mr. W ahlbom^
cc or rather Mr. Linnaeus , ( i ) ut cannabis fe-
<c minifera, unum alterumve ferat florem
“ ftaminiferum, quo nonnullae feminae im-
cc pregnari pofiint ; quod Camerarium lu°
“ fit.” Granting this fhould happen fome-
times, and that thefe Gentlemen have feen it,
(which, however, is not here afierted) ; yet,
3 may fay, that I believe they are the firft that
ever faw it 5 and that this is not enough to re¬
move Camerarius s doubt, nor to weaken the
argument
(z) Amaen. Acad. vol. 1. edit. Lug, Bat, 2749.
P- 99*
PHYSICAL and LITERARY. 23*
argument drawn from the above experiments*
unlefs they can fay, that the feed-bearing
hemp carries always one or more fuch ftami-
niferous flowers ; or that the cannabis of Ga-
tner arias , and the other abovementioned,
had really fuch flowers on it, which they
cannot aflert. For my part, I can declare,
that, tho’ I fearched very carefully for the
feed of the hemp plant, (k) I could fee no¬
thing like ftamina on it ; neither on the feed¬
bearing plants of the fpinacia , mercurialise
bryonia , either before or fince I read Mr.
Wahlbom s Sponfalia Plant arum,
20. Hence I think the pofition of that
learned botanift Julius Pontedera, viz, cc A-
<c picum liquorem embryonis foecundationi
€C in omnibus plantis non efle neceffarium,”
to be a demonftrable truth, which neither
authorities nor arguments can refute. How¬
ever to clear up further this controverfy, I
fhall conlider the arguments advanced by the
moft famous fexualifls, as they are fummed
up by the very learned Carolus Linnaeus , in his
Fundament a Botanic a ; explained by Jo, Gef-
nerus
(k) Exp. 2,
232 ESSAYS AND OBSERVATIONS
items (/), and demonftrated, they fay, by Jo.
Wahlbom {m)y and Car, Linnaeus himfelf (n)«
2i. Generationem vegetabilium fieri, me»
diante pollinis antherarum, &c. ut fupra, N°
2 5. confirmat (or, as in former editions, di£li-
tat) i.oculus , P. B. § 145. How the eye
fhews or confirms the generation of vegeta¬
bles, to be thus effected, is explained three
different ways. For,
1. “ Ipfa autopfia (fays J. Gefner) hunc
££ generationis adtum edocet. Primus qui
££ florum connubia vidit, cel. D. Seb. Vaillant
£S ( 0) tam eleganter defcribit, ut nemini de
£C hac re dubium fupereffe poffit. Ita autem
£C cl. Vaillant, £C Quoties acciderit, ut in ea-
££ dem ftirpe flores gerantur fimul, quorum
£C hi foeminiria tantum, illi autem mafculina
£c et foeminina conjundta organa cingunt, ar-
££ redtio tumorque organorum mafculi norum
in his tam fubito eontingit, ut lobuli gem-
£C mse
(/) Differtationes Phyficae de Vegetabilibus, Lugd. Bat.
3743. 8vo conjunctum cum C. Linnaei oratione de necefiitats
peregrinationum. Explicant elementa botanica Linnaei.
Lin. bib. vol. p. 1 74.
[m) In the Sponfalia Plantarum, Amaen. Acad. vol. t. p,
61. ad 109.
{#) In Phil. Botan.
(c) In lib. de ftru&ura florum. . .
PHYSICAL and LITERARY. 233
c* mas flofculofas cedant illorum impetui, at-
<c que hincinde femet expandant, mirabili me-
4£ hercle velocitate, et extemplo quam vio-
lentiffime fcecundam explodant, omnem-
<c que uno impetu ejaculentur genituram,
*c diffufa nimirurn pulverulenta nubecula,
<c Ipargente quaquaverfum foecondationem
cc arvi genitalis. Vix venereus hie Indus ab-
C£ folutus eil, quin illico florum labia, aut lo-
“ buii, ad fe invicem accedant eodem qui-
dem, quo a fe mutuo recefierant, celeri**
££ tatis impetu, veteremque ita formam fta-
,c tiin renovent. Apparatum hunc artificio-
u fum facile fpedtare datur in parietaria . Sed
u accedas opportet hora facra veneri, aurora
eft quae favet his congreflibus ; ubi vero
agere lenuunt fatis opportune, aciculae a-
:c Pice> leniter modo, flimules. In herma-
,£ phroditis, ubi duo fexus conjundti haben-
lUi, muitum aoeit ut tanto impetu explo-
dj.Lur. Pierique enim fiores, praecipue
“ nutantes, in quibus piftillurn obliquum
iiAia ftamina pontum habet, adum gene-
1 at i on is floribus claufis exercent, dum ftig-
ma adhuc intra medias antheras contine-
tur.;J Thus Mr. Gefner. (p)
G
(/>} Ditr. p. 86.
or
22. Allow
234 ESSAYS and OBSERVATIONS
22. Allow me here to chferve, in the firft
place, that this artificial apparatus ( q ) was feen
and defer ibed by John Bauhinus , long before
Vaillant was born (r), and tranferibed botn by
Morifon and Ray in their hiftories of plants,
tho’ Vaillant mentions none of them : and,
fecondly, that this feems to afford a ftrong
argument againft the impregnating virtue of
the d nil of the apices . For, according to
Linneus himfelf, “ parietariae hermaphroditic
€C flores duo continentur involucro piano hex-
« aphyllo. Calyx monophyllus, magnitude
« ne involucri dimidiati. Stamina filamenta
« quatuor calyce longiora, iliumque expan¬
se dentia. Faemineus flos unus, inter hernia¬
s' phroditos ambos, intra involucrum ; cum
calyce ut hermaphroditi (/).” Now, fince
the (lamina of the hermaphrodite flowers,
as well as the germen of the female flower
betwixt
(q) Tout, cette mechanique, Vaill.
(r) 44 Parietariae flofculi conferti circa caulem ex foliorum
fiC alls, floccos coccinei ferici imitantur, primulum e nodulo
« emicantes : poll fe ilamina oftendunt obfeure, exalbo pur-
44 purafeentibus apiculis, involuta, quae fi ftylo evolvere co-
et neris, fubfultim excuffo pulvere cum impetu, fpedlaculo
44 jucundo, fe expandunt repanda, in medio ieminis rudimen-
44 turn circundantia.11 I. B» 2. p. 976.
(/) Gen. pi. p. 494.
PHYSICAL and LITERARY. 235
betwixt them, are contained, in one common
involucrum , and the apices do not ejeft their
duft, until, by the ftraightning, or ftretching
out of the formerly crooked Jlamtna , the
common involucrum is burft open, and the a-
pices raifed in the air ; fince no fooner do
they find themfelves free, and eredted high
enough above the involucrum , than immedi¬
ately, by a fort of explofion, all the duft is
entirely, with great violence, thrown out ;
and fince the leaves of the involucrum clofe
up again, as quickly, and with as much force
as they feparated, and refume their former
figure (t) ; does not all this fhew, that the
duft is not by nature defigned to impregnate
the feed, but to be carried away by the winds,
left it fhould infedt it, by falling on the ftig-
mata ; and that autopfia teaches the quite con¬
trary to what Mr. Gefner alledges.
23. <c It a
(*) “ Ita quidem, (adds Mr. Vaillant), lit difficillimum
“ foret credere, flores hofce ullarn vim paffos efle, nifi vel ipfe
aftum hunc vidifiet oculus.vel adhuc cerneret caduca fcele-
“ ta magnanimorum heroum, aliquumdiu eredla in campo
“ confli&us, ubi apluftrium inllar, jocularios experiuntur lufus
yolitantis zephyri.’*
236 ESSAYS and OBSERVATIONS
23. ec It a fefe in plantis habere, (fays
€t M. Wahlbom) didlitat primo oculus. Flo-
cc re florefcente, et polline antherarum vo-
cc litante, quod ftigmati pollen inhaereat, pri-
£C raa fronte obvium eft (u)L But it is not at
all obvious, far lefs does the eye fee, that ge¬
neration is thus accomplifhed ; for this duft
as often befpatters thzpetala, &c. Neither
does what he adds concerning the florefcentia
molae triccloris , gratiolae , iridisy campanulae
et fyngenefianim , in the leaft favour him.
For, tho’ all he fays were true, thefe make
but a very inconfiderable part of the vege¬
table kingdom. Yet they feem rather to
make againft him. For in thefe compound
flowers, which he calls fyngenejiae , the
' anther ae font lineares, eredtae, lateribus
cc coalitae in cylindrum tubulatum. Stylus
filiformis eredlus ftaminum longitudine,
£C antherarum cylindrum perforans. Jligma
c‘ bipartitum, laciniis revolutis, patentibusA
Lin , Gen. pL p. 370. To which if we add,
that thefe anther ae fplit, and emit their duft,
on the outfide, not in fide, of this cylinder ,
while the Jligma is commonly pretty far a-
bove
/ . ,
{y) Amaen Acad. 1. p. 90*
PHYSICAL and LITERARY. 237
bove it ; what can reafonably be inferred
from this ftrudture, but that Nature deligned
this duft fhould be thrown away as ufelefs^
if not hurtful to the Jlylus ?
Again, the Jlylus of the campanula is com¬
monly much longer than the Jlajnina , and
briftly a little above them, as it were to hin¬
der their accefs to the Jligma . The Jlamina
of the iris are hid under the outhde of the
fegments of the jligma , the depreffed petala
being frequently bearded or hairy under
them. So no plants could be here more
improperly alledged 5 for, by the firucture of
their flowers, it is evident, that the pollinis il-
lapfus fupra Jligmata nuda is impoffible : nor
can Mr. Wahlbom deny it ; cc campanula , (fays
*c he) a caeteris in eo differt, quod pulvis la-
cc teri hifpidi ftyli adfigatur, et exinde per
cc certos canales iligmati communicetur. I-
“ ris particularem nobis oftendit ftrudturam ;
“ ftigmata enim fefe dilatantia, antheras om-
<c nino operiunt ; ilium tamen ad petala re-
cc ferunt fitum, ut, aura fubeunte ftigmata*
<c pollen per rimas iilorum afcendat.” What
eye ever faw thefe canales , or rimae , with
the pollen rifing in them ? how, or why ri {q
to th t Jligma thus fituated ?
A§
238 ESSAYS AND OBSERVATIONS
As for his obfervations on the viola tricolor ,
I pafs them, becaufe nothing to the purpofe 3
and alfo too fmutty for BritiJfj ears. But let
us hear what the great Linnaeus by himfelf
fays:
24. “ Generationem vegetabilium fieri,
<£ &c. (fays he) confirmat oculus . Pollinem
C£ intrare germina credidit Morilandus 3 ejuf-
<c dem eflentiam extrahi, mediante ftigmate
cc madido, ftatuit Vaillant 3 pollinem aceris
cc rumpi in humore vidit Bern. JuJjiaeus 3 om-
tc nem pollinem in humore explodere auram
4c feminalem, confirmat Needham (#).” But
Norland? s opinion is fully confuted by Vaillant,
who maintains only that the vapour, or vola¬
tile fpirit of the male duft, enters the trachiae
of the Jlylus 3 but not a word can I find in
his difcourfey concerning the extraction of the
effence of the duft by means of the moift
fligma : and, aitho' it ftiould all burft in
moifture, I do not fee how it thence follows,
that it thus fends out an aura Jetninalis 3 e-
fpecially, fince it does not appear, that
the Jligmata muft necefiarily be moift in or¬
der to fertility : and it is obferved by Mr,
Wahlbom
(x) PliiL 9E0
PHYSICAL and LITERARY. 239
Wahlbom (y), That, “ In omnibus fere flo-
£C ribus confpicitur, quomodo, aere humido,
<c flofculos complicant, ne aqua pollen attin-
cc gatT By no means, therefore, can the
eye be faid to confirm the fexual fcheme.
25. The fecond argument for this fcheme
is taken from the proportion which the an¬
ther ae bear to the flylus .
cc Ex proportione quoque, (fays Gefnerns)
u (#), verofimiliter judicamus, cum, pro
cc magnitudine et numero feminum, ipfa quo-
cc que (lamina maiora fint vel numerofiora.”
But that this is evidently a miflake, will ap¬
pear to any one that will take the pains, to
compare Linnaei monandriae with his poly-
andriae ; or the cannacorus with the prunus ,
and other (loned fruits : the fyngenefiae have
five Jlamina for one feed, and that, not feldom,
a very (mail one : the umbelliferae , as many
for two feeds, &c.
cc Ita lefe in plantis habere diddtat fecun-
ic do proportio : plerumque (lamina et piftilla
eandem ferunt altitudinem, ut eo melius
€C ad fligma pollen, mediante vento, accedat 3
£< in
(y) Amaen Acad, i, p. 95.
(z) DiiTert. p. 91.
24o ESSAYS AND OBSERVATIONS
cc in quibufdam vero non, ubi fingularis ob-
£C fervatur proceffus foecundationis (a)” But
plerumque diditat nihil, efpecially lince there
are a great many genera , where no fuch pro¬
portion or lingular procefs takes place, as in
almofl all the flofculoji , Jemi flofculoji , radiati ,
liliaceiy caryophyllrei , and of the iix
plants inftanced as lingular, in three* viz.
dianthus , ntgella , and pajjiflora ; the pi/tilla, any
curvature notwithftanding, continue high
above the flamina (b)>
This argument is thus explained by £/;z-
£C Property: lligmata fefe fledere'ad
“ antheras, dein exferi ex diantho , pajjiflora ,
4C ntgella , patet. Piftillum ubi breviffimum,
“ connivent antherae. fupra lligmata : y&V-
cc frag a, parnajjia. Connivent dum efHant pol-
Jinem antherae in celofla. Comprimit corolla
cc digitis antheras ad lligmata in Teucrio (e).”
Here not a word of proportion confirming
his fcheme 5 no inltance of it ; but only rea-
fons for inequality. No matter, therefore,
whether it be fo in thefe or not.
26. The
(a) Wahlbom, Amaen. acad. 1. p. 90.
(b) See Pontedera for more inftances. AnthoL 3,2, c 8.
(c) Phil. Bot. p. 91.)
PHYSICAL and LITERARY. 241
26. The third argt is, cc Ex loco ftaminum
et piftilli, non leve argumentum petere pof-
<c famus j nam in plerifque plantis, floribus
hermaphroditicis preditis, {lamina ambiunt
cc ovarium, et ea ratione ut maxima pars ge~
c< niturae ad ftigma accedat.” Gefnerus (c).
Can the / lamina furround the ovarium , in the
monandriae , diandriae , &c ? but this needs no
anfwer; neither what he adds concerning the
pijlilli fabrica, and anther arum mater icsy which
is nothing to the purpofe.
tc Tettio, locus. Etenim ftamiiia plerumque
<c piftillum ambiunt, ut ventorum ope femper
<c quidquam pulveris attingat ftigma.” Wahl-
horn (d). But the learned author cannot but
know, that the Jlamina {landing round the
piftillum can never prove the neceffity of the
duffs falling on the Jligma of every plant, in
order to its foecundity 5 efpeciall'y when this
is not always their filiation. He adds, ££ Mo-
<c neciae fores mafculi plerumque fupra flo-
<c res foemineos collocantur, ut pollen eo me-
£C lius in piftillum decidat and inftances
ricinus among others: but, fure I am, the
ricinus vulgaris B. p. has all its female flowers
H h above
(c) Differt. p. g,
{d) Amaen. Acad, i. p. 91,
242 ESSAYS AND OBSERVATIONS
above the male flowers ; the jiigma of the
upper mo ft being commonly feme inches a-
bovethe neareft f lamina .
fC Locus. Nunquam piftilliferae fponte
*£ nafcuntur fine ftaminiferis in eadem terra;
C£ prodeunt ex eodem femine ambaeA Lin¬
naeus (e). But this cannot be proven. Yea,
Gamer arius afTerts the contrary (/). But2
granting it true, it proves nothing, confirms
nothing,
2 y. Argument 4th, C£ Ex tempore quoque
sc vegetationis harum parti urn concludere
“ datum eft : namque in antheris, flam in a
C£ farinam foecundantem eo tempore conti-
nent, quo piftillum viget, deinde, excuflb
££ pulvere peradta foecundatione, perit ft a men;
g£ fuccus copiofior in piftillum devolutus, ef-
fCficit ut frudlum maturefcat,” Gefnerus (g).
But the (lamina fpinaciae , mercuriality canna¬
bis s mays, ] uni peri, violae martiae , &c.
Hied their duft commonly before their jlig-
rnata are vifible.
€£ Quarto tempus. Primum hie atten-
*£ dendum venit quod flam in a et piftilla una
sc proveniant,
(e) Phil, Bet. p. 91 .
if) See No 10. fupra.
( g) Differt, p . 9 1 .
PHYSICAL and LITERARY. 243
/
<c proveniant, exceptis tantum paucifiimis.
c£ Alterum, quod ubicunque flores mafculi
cc diftin£tis a foemininis gaudent thalamis, aut
cc in eadem aut diverfa planta, et ubi mafculi
cc flores nec perpendiculariter fupra foemineos
cc erecii funt ; ibi, florefcentia ante foliorum
“ exortum peragatur, neceffe eft 3 ne, foliis
cc intervenientibus, inhibeatur foecundaiio :
cc ex.gr. in moro,vifco, mercurial! per entity &c.5S
Wablbom (h). How juftly thefe three are in-
ftanced, any body may judge. But finee he
admits of exceptions, as to the firft notandum 3
and many other plants emit the flowers be¬
fore the leaves 3 this argument proves no¬
thing.
£C Tempos. In declinis flores ante germi-
£C nationem foliorum plerumque prodeunt, ne
cc folia tegant piftilla 3 falix , populus , cory-
£C las, &c.” Linnaeus (/). Here, as com¬
monly, we find plerumque 3 and an imagina¬
ry reafon .
28. Argument 5th, viz. pluviae 3 “ Fit in-
cc de ut, dum pluvia eluit pulverem ftaminum,
££ germina piftilli decidant, aut in frudlus
££ nafcantur abortivos, ut ftillant vites, perco-
££ quantur.
i 3
[h) Amaen. Acad. i. p. 92.
(j) Phil. Eot. p. 91.
2U ESSAYS and OBSERVATIONS
£C quantur, marafmo exarefcant, locum con-
4£ cedant infeftorum nidis et eorum evoluti-
e£ oni, ut fruges uftiiagine pereant, et quae
“ font alia vitia. Sedulo itaqueNatura ubique
££ fqlicita fuit, ut genitura illibata ad piftillum
££ perveniret/5 Gefnerus (/&). But how does it
appear that fuch are the confequences, of the
duft’s being wafhed away by rain ? Has too
much moiflure no bad effedts, after the fiami-*
na have ihed their dufts ? Does it not fre¬
quently rot the plants ? $cc.
S£ Qtiinto pluviae . In omnibus fere fieri-
££ bus confpicitur, quomodo, urente foie, fefe
^ expapdant, vefpertino vero tempore, et
£C acre hum i do, flofculos complicent, ne
£C aqua pollen antherarum attingat et coagu-
fc let, quo fa&o, ad ftigmata efflari nequeat ^
4£ at ftigmate, minim fane ! femel foecunda-
i£ to, nec vefpere, nec pluyia ingruente,
fefe contrahant flores,,? Wahlhom (/). But
our author knows, that many plants clofe
their leaves in the night or in rain ; as
the acaciae , mtmcfae , &c. that many open
iheir flowers in the night, and fhut them
when
[k) DilTert. p.
{/) Amaen Acad', i. p. 93,
9
PHYSICAL AND LITERARY. 245
•when the fun is hot ; as fome cerei, ketmiae,
xyla, lychnis nocli flora, mirabilis peruvial
ra, &c. fli) Does not the paflion-flower keep
open in the night as well as day, until it Ihut
up roi good and all, and that whither it be
fun-fhine or rain ? He adds, “ Secale florens
“ antheras filamentis infidentes exferit, quo
“ tempore, fi pluvia cadit, pollen congloba-
tur, hincque annonam difficiletn auguratur
agiicola, nec immerito ; grana enim im-
minuuntur exinae, quod plenque flofculi
" abortum paffi fint.” That fecale, triticum ,
many gramma , plant agines , pimpinellae, &c.
thruft out the apices on pretty long Jiamina ,
when in flower, I deny not ; but that rain at
tticit tiinc caufes icarcity ot any of them, I
never obferved; and aitho it were granted,
that tins commonly happens, How does it
appear that rain caufes the flofculi to abort,
or this abortion caufes fcarcity of fecale ?
fmce, at the fame time, the other plants are
fufliciently fertile, yea the manner of flower¬
ing in iome of thefe plants, feems to afford an
argument, not contemptible, again fi the fex-
ual
' ^ C< M’.rat)5jls eft planta quae tam fpeciofos fl ores nodi
" atrae objicit, et fereno diei fubtrahit.” Lin. H. Cliff;
?• 54* • '
{ - 1
246 ESSAYS AND OBSERVATIONS
ual fcheme. For in fecale and triticum too*
there are three jlamina for one germen , both
included within, and well covered by the
fame hulks (be they a corolla or calyx , or both,
no matter here) before the flowering time.
Now if the dull be neceflary to the impreg¬
nation of the feed, and, in order to this,
it mu ft fall on the jligma ; Why is not this
accomplilhed, before the covers open ? Why
are the jlamina fo long ? Why do they
thruft out the apices fo far from their ftigmata ,
and throw out, if not all, at leaft the great-
eft part of their dull, in the common air ?
Does not all this look as if this duft, was not
deflgned by Nature for the impregnation of
the feed ? as is often noticed.
sc Pluviae (fays Linnaeus') hi) combibunt
*c pollen, ut in ftigmata cadere nequeat ;
*c hortulanis notiflimum in drupiferis, (fo
C€ he calls the amygdalus , perjica , prunus ,
cc armeniaca^ cerafus , laurocerafus , &c.) et
cc pomiferis. Agricolis deteftabilis in agris
4C fecalinis, (why not alfo triticeis i ) Fu -
<c mus idem etiam facit, abforbendo humi-
“ dum ftigmatis.” So the Jligma muft nei¬
ther be wetted nor dried. But this is fully
anfwered
(») Phil. Bot. p. 91.
PHYSIC AL and LITERARY. 247
anfwered above. Non caufa pro caufa is here
very frequent.
29. 1 he fxth argument, which the
Sexuahfts triumph in, as a demonftration of
tae<r c!oitrine, is taken from the culture of
the palm-tree. “ Inftar omnium argumento-
rum efle poieit (lays j. Gefnerus) (0) mo-
“ dus 9U0 foecundatio palmae dadvliferae
“ ad °^inendos dadylorum frudus matures,’
“ aPud perfas snftituitur, a cl. Kaempfero,
“ lnhls !ocis* annotates.” It would be too long
t° tranlcribe all that modern authors have
faid concerning this tree. The reader may,
if he pleafes, confult John Leo (p), Proffer
Alpinus (q), Hadgi Mujlapha A?a (r), Emel-
bertus Kaempfer (,), Pere Labat Cbrift.
Got. Ludwig. ( u ), &c.
30. These authors are agreed only in this,
that tne date-bearing palm-tree has no flowers:
and unlefs the flowering or male palm-tree be
fufficiently near, or the dull of its apices be
, , n._ feme
(°) Diflert. p. 85.
{p) Harris collect, vol. i. p. 347.
(9) -^e pl* Aeg. p. 24.
(r) T. Juft. p. 69.
M Amen. exot. p. 706.
(9 Voyage aux lflos de L’Amerique, Hague edit. vol. 1,
part 2. p. 209.
(«) In J. Gefner. diftV p. 86.
t4^ ESSAYS and OBSERVATIONS
feme how conveyed into the Jpatha of the
female; its date ftones will not grow. I fhall
pafs the very wide differences among them,
as to the manner of conveying it ; and only
obferve, that without the influence of the
male, the female will either be barren, or
caft her unripe fruit, according to the anti-
ents, and Alpinus ; that the dates will want
ftones, be harfh, and not eatable, except by
camels and cattle, Hadgi. C( Omnia fua fru-
cc ftuum rudimenta, indeclinabili abortu di-
tr mittunt, Kaempfer . cc In fructu pulpae loJ
cc co adeft cortex durior, ficcus, adftringens,
4£ ofliculum vel nullum vel tenue,” Ludwig .
which are all contradicted by Lab at.
31. c * It is pretended, fays that reverend
father, that the date-tree is male and female;
that the male bears bloffoms, but no fruit,
that being left to the care of the female but
that fhe would carry none, if fhe had not the
male by her, or at leaft within fight of her.”
lam lorry that Icannot fubferibe to this opi-
mon of the naturalifts, but it is a mod certain
experiment, diredly oppofite to their fenti-
ments, that hinders me ; for we have a date-
tree faefide our monaftery in Martinico , which
carries fruit, tho’ fingle : whether it is male
PHYSICAL and LITERARY, 249
or female, I know not 3 but this I know for
certain, that there was not another of the
kind within two leagues of it. Whence we
may conclude, that the prefence of the male
is not neceffary to render this tree fruitful,
as naturalifts pretend A Fie fays indeed al¬
io, that the fiones of the dates of the iflands
will not grow ; fo that thofe who would raife
palm-trees , are obliged to plant the Barbary
dates; and that dates do not ripen fo perfect¬
ly in Martinico and Guadaloupe , as they do in
Africa , in Afa, or even in St. Domingo A
For altho' our dates, fays he, become foft,
yellow, and as it were lufcious, and in
a word, appear perfectly ripe ; yet they
Rill retain a certain fharpnefs, which fhews
they want at leaft fame degree of maturity A
Thus Pere Lab at. 1. c.
♦
fo. Banhinus («) relates, that he faw only
one date-bearing palm-tree at Montpelier <
Centeiimum annum fu per are creditor, (fays
<c he) et vulgo ibi perfuafum, ante grandem
aetatem fru&um non proferre, et vix ante
“ quin qu age iimum annum, ut quidam per-
sc hibebantA Hence Pont anus s fiftion is ea-
fily accounted for, if there be any truth in it $
I i and
(«) Hi.lt* s p. 360..
250 ESSAYS AND OBSERVATIONS
and perhaps fome others, particularly con-*
cernirig the amours of thefe trees ; for which
fee Pliny (x), and Caffianus Bajjus (y).
39. But I cannot omit the opinion of He¬
rodotus , the mod: ancient author, who has left
any thing concerning the ufefulnefs of the
male, to the female palm-tree*, “ In Baby -
lonis agris, fays he, palmae magna ex parte
cc frudtiferae proveniunt; ex quibus non folum
ce cibum, vinum, et mel conficiunt, fed eti—
€C am eodem modo quo ficus curantur. Pal -
cc marum enim, quas Graeci mafculas vocant,
cc fruftus palmis glandiferis alligant, ut earum
€C frudtum maturet culex fubiens, ne ex ar-
bore is defluat. Ferunt enim palmarum ma-
res (z) culices in frudtu, quemadmodum
C£ caprificiA Thus Herodot , as rendered by
Bed. a Stapel{a ). Whoelfewhere {b) quotes a
famous traveller for fuch a culture of this
tree, as confirms Herodofs opinion (c).
Again
(x) L. 1 3. c. 4.
(j) In Theoph. p. 103,
(z) ^riva.
(a) In Theoph. p. 115.
(b) P. 103.
( c ) “ Agricolae etiamnum, ut refert dodtiffimus Guil-
land, in Arabia, JEgypto,Mefopotamia, Iudaea , Phoenicia , et
tota Syria, volentes cavere ne foeminae, aut fterilitatis nox-
“ am
PHYSICAL and LITERARY. 251
Again Joan. Vejlingius , who was long in
Egypt, differs not a little from Alpinus , as to
the culture of palm-trees there : cc Caufa tarn
foecundi proventus (fays he) in telluris ha-
cc bitudinem referenda eft, arenofam fcilicet
<c et falfam, plantae huic gratiffimam. Vidi
<c his locis in palmarum veluti fylvis, terram
“ copiofiffimi nitri calida nive late confper-
cc fam, vel aquis Nili, vel rofcida nodium
u humiditate fervidiore foie peruftis. Nec
<c opus hie mar it all cinere palmae effoeminatae
“ vigorem incitare. Flantibus enim ab au-
cc ftro per ^Ethiopian!, et fteriles Arabiae de-
cc fertae campos urentibus, ventis 3 ingens ni-
cc trofi pulveris fublata vis, abunde cacumi-
na
e< am incurrant, aut fruOum, quem aliquando imaginations
££ libidinis, ut ita dicam, concipere folent, ante maturitatem
££ amittant, ita ordinant utriufque fexus palmas, ut mares eo
££ faltem intervallo a foeminis diftent, quo pulvis, ventorum
“ flatibus a foliis mafcularum fublatus, in foeminarum folia
“ incidat ; idque fatis ad foecunditatem, et fruftus matura-
<£ tionem facere compertum ed. Sed mirum diclu ! quod fi
££ qua procul a mare abditerit, ut neque pulvis, neque aura,
££ pdorve ejus, ad earn permeare poflit, excogitaverunt colo-
“ ni funem a tnare religatam ad foeminam ufque pro due ere ; at-*
“ que ita quad maritali vinculo copulatam, mafeuii virtute
<c clanculum per funem irrepente, foecundam fieri, quae prius
“ in ea fterilefeebat folitudine.” It is eafy to conceive how
infedls may creep along a rope, but not how a powder or
dud can be thus conveyed from one tree to another.
252 ESSAYS AND OBSERVATIONS
cc na palmarum vegetat.— Meminique fic o°
cc nuftum fuifle dadylis fuis unicum race-
cc mum3 ut eum attollere a terra prae pondere
£< vix fuflinerern (</).” And Alpinus himfelf
is obliged to own, that the fruitfulnefs of the
palm-trees in the deferts of Arabia , is not ow¬
ing to any artificial culture, but to the winds
carrying the duft and flowers of the male to
the female (e). Is it probable, that nature
has left the fertiliiing of fo ufeful a tree, to
the uncertain motions of the air ?
Besides, that great and curious botanift
! Tour report , after mentioning the opinion of
5 Theophrajlus , Alpinus , and others, concerning
the male palm-trees , adds, £C Cum in Hifpania
£C Baetica, palmarum feraci, a prudentioribus
viris de hac re fcifcitarer, certum nihil ac-
cc cipere potui. De lupulo certius loquor. In
cc Horto Regio Parifienfi, luxuriat frudibus
v quotannis onuftus. Qui vero floribus gau-
C£ det, non occurrit nifi in infulis Sequanae et
5C Matronae, longe diftantibus : in Horto Re-
£C gio tamen femina profert ” ( / ).
This
(d) Veiling in Alpin. c. 7. p. 1 1.
(e) Y. Alpin. de plant. Mg. p. 25 =
If) JnfL p. 69.
9
PHYSICAL and LITERARY. 253
This objeaion againft the fexes of plants
drawn from the lupulus , appears to be
ftrengthened by the anfwer made to it ;
which is this, ££ Humulus duplex omnino eft $
“ unus floribus fuperbit ftaminiferis, alter pif-
€£ tilliferis 5 idque quod fniBum vulgo vocant,
“ eft calyx tantum explicatus et elongatus :
<c hinc humulus , quamvis foemina, nec foe-
C£ cundata, conos tamen proferre valet. Hoc
cc Tournefortium decepit, nefexum plantarum
<c agnofceret, quum lupulus (foemina) in hor-
“ to Parifienfi luxuriabat, frudtibus quotannis
“ onuftus ; qui vero floribus gaudebat (mas)
cc non occurrebat nifi in infulis Matronae et
€C Sequanae multum diftantibus (g). Idem
Cf fit in moro et blito, cujus baccae calyces funt
cc fucculenti 3 minime pericarpia, feu ova-
£C ria ”(h).
34. For I am at a lofs to find wherein
Tournefort was deceived. He gives an accu¬
rate defcription, as well as elegant figures, of
the parts of the flower and fruit, as ftanding
on different plants (/), without which the
charafter of the humulus , in Linnaei Genera
plantarum
(, g ) Tournefort, Hag. p. 69.
(b) Amaen. acad. 1. p. 99.
U) Vid. T. p. 535. t. 309.
$54 ESSAYS and OBSERVATIONS
plantarum (k) is not very intelligible to a be¬
ginner. But he calls the enlarged calyx, Jru -
Bum : the cones he calls fruBus ; and fo
they are, in the moft proper fenfe of the
word. T Annaeus himielf, in his p undame j it a
hot . teaches, that “ effentia frudus in femine
« confiftit”(/ ) > an d, in his Philofophia Bota -
nica (m)y ££ frudus ex femine five pericarpio,
« five non tedum fit, dignojfciturV No
matter therefore, whether ye call thefe cones
calyces elongates , or fruBus , if they contain
feeds : and Tour ne fort expreflly adds, €£ In
« horto regio femen profert which Mr;
Wahlbom is pleafed to omit, for what reafon I
fhall not fay. As for the morus and blitum ,
I fee not why their baccae fucculentae may not
be called fruBus alfo s efpecially fince Lin¬
naeus {n) gives blitum a pericarpium 3 and de¬
fer ibes a pericarpium to be <c vifeus gravidum
C£ feminibus, quae matura dimittit ”(0) : and
confequently Wahlbom and he don’t well a-
gree. But, to return to the palm-tree ,
35. 'Sexto*
(*) p- 477-
[l) § 88.
{m) P. 56.
§
(») Gen. pi. p. 5,
(0) Phil. Bot» p. 53.
PHYSICAL and LITERARY. 255
35. cc Sexto, Palmicolas palmarum fpadi-
• tfc ces mafculos divellere, eofdemque fupra
foeminas collocare, memoriae mandarunt*
cc Theophrafusi P limits, Alpinus , Tournefor -
<c tins , Kaempferus , alii : quo neglefto da-
£c dtyli acerbi, et nucibus deftitutae, hunt,”
Waklbom ( p ). This is anfwered above (N° 3 1 ) :
then the author gives a long paragraph out of
Kaempfer (y) ; as does Gefnerus (V), from the
fame page ; yet they differ widely, I have
not at prefent Kaempfer by me ; but may be
allowed to notice one thing, not very credi¬
ble in each, according to their principles, viz.
Nemus foecundari univerfum poteft ab una
phoenice florida,” Gejher. cc Singulare quod
€C fpadices exficcati ad thalamos apti funt, et
C£ in annum pofterum, falva virtute, affervari
€C poffunt,” Wahlbom.
36. “ PALMicoLiE : notiffima Theophrafo,
€C Phmo , Kaempfer o, aliifque. Pifaciae cultu-
cc ra in Archipelago : Pourne fortius. Caprifi~
sc catio veterum, et adhuc in Archipelago^
£C per infedla.” Vid. differt. noftr. de ficu,
Linnaeus
iP) Amaen, Acad. i. p. 94,
(q) Amaen. p. 706,
(r) Differt. p. 85.
25o ESSAYS AND OBSERVATIONS
Linnaeus (t). Neither Theophraffus , Pliny, nor
ILaempjer, relate the culture of palm-trees, as
from their proper knowledge ; and are
contradicted by an eye witnefs, Fere Lab at.
As for the culture of pijlacia in the ArchL
pelago, for which Lournefort is alledged, I
cannot find any fuch thing in his works.
Such a culture, indeed, is mentioned by the
editor of M. Geoff? of s Materia Me die a [u],
as praCtifed in Sicily : but he neither fays he
was in that ifland himfelf, nor tells us who
informed him. However, if fuch is the cul¬
ture of the pijlacia , either in Sicily or the
Archipelago , it feems to be very modern, and
founded on the imaginary impregnating vir¬
tue of the duft of the apices 5 and, no
doubt, the terebinthus will foon be treated the
fame way, it can do no harm ; tho’ it is
not very probable, that deficiente tali impreg¬
nation e frublus abortiant in this tree, more
than in the palm-tree .
3 7* Concerning caprification, if you con-
fult Lheophrajlus (x), Pliny (y), and Tourne -
fort
(t) Phil. bot. p. gz.
(u) T om. 2. p, 417.
(*) Be caul', pi. 1. 2, c. 12.
{y) 1. 15. c. iq.
PHYSICAL and LITERARY. 257
fort ( )., or Pontedera (a) only, who quotes
all the three, together with the learned DiC-
fertation our author refers to, which I take
to be Cornelii Hegardt Hijioria naturalis et
medica ficus fi) ; it will be eafy to judge, whe¬
ther it is at all probable, that the fig infetls
carry the duft of the caprificus to the unripe
figs, and thus impregnate the feeds (c).
K k 38, If
(z) Voy. let. 8.
{a) Anthol. 1. 2. c. 33, 34, 35.
[b[ In C. Linnaei, Amaen. Acad. vol. i. p. 213. 243.
(c) “ Cnpido ficus nobis dicitur, quem antiqui pfenem feu
te infeftum vocarunt jicarium , et Pontedera, Anthol, 172,
<c defcripfic, eftque fpecies ichneumonis. Hifce ichneumo-
nibus jam mutatis, alifque inftrudtis, tempus adeft, quo
“ caprificus, feu ficus mas, florefcit, h. e. farinam edit anthe-
“ rarum ; tunc ichneumones e caprifici cavitatibus, farina,
“ tnolitoris inftar e mola fua prodeuntis, obdudi evolant, et
“ conjugibus acquifitis de ovis pariendis foliciti funt : hinc
“ ad fingulos grofibs tranfvolantes, cavitates ficus foeminae,
“ dolii infiar, clavis ferreis vel fpiculis feu piftillis ab omnibus
<c lateribus intus completas, intrando, non poifunt non fan-
«* nam illam, qua contedi funt, excutere. Patet igitur hoc
“ modo, Jicum hanc foeminam facillime irn pregnant’ Thus
Mr. Hegardt, Amaen. Acad. 1 p. 231. A fine appen¬
dix for Pont anus’s poem ! But,
According to Pontedera, “ Ficarii culices, forma
i( ad vefpas, nafcendi autem modo ad mufcas, accedere mihi
6i videntur. Ut primum groffi grandiufculi fadi apertum fun-
*‘-dum oftendunt, ingrediuntur foemellae, et ex infimo ven”
4‘ tre produda tuba, foeturae in frumentis nidum excavant, et
ovula
258 ESSAYS AND OBSERVATIONS
38. If it be ftill alledged, that the infoe-
eundity of the date ftones of Martinico de-
monftrates the foecundating virtue of the male
duft ; I anfwer, by no means : for Pere La-
bat
At ovula deponunt. Nafcuntur in his vermiculi, qui deinde
44 nymphaeevadunt immobiles, durae, corpore oblongo, ca-
44 pite cum dorfo luteolo, caetera primum albae mox nigrae.
44 Perforato deinde nido, exit animalculum, plerumque non-
64 dum pinnis explicatis. Egreffum ftatim fenedtam deponit
“a capite incipiens. Tuncflavum cernitur, quod tamen
54 mox exficcatum nigrum evadit. Dum vero involucris
44 fpoliatur, hue et illuc revolvitur ; et propterea apicum
44 pulvifculo, quo tota pomorum cavitas repleta eft, infarci-
44 tur, quippe molliulculum. Quare e grolfis egreffum, et
64 foie exficcatum, pulverem difeutit ad hunc modum;
44 ftatis quatuor anterioribus pedibus innititur, et duobus po-
44 ftremis abdomen, lumbos, pinnas pulvere mundat, iterum
44 atque iterum cruribus detergens ; deinde quatuor pofteri-
44 oribus fefe librans, duobus anterioribus caput, dorfum et
44 cornua purgat. Quemadmodum feles et alia elegantiora
44animalia folent. Tunc, depofito onere, evolat.” An-
thol. p. 174. And p. 175, he adds, 44 Hujufmodi animalcu-
44 iis tota groftbrum caro et frumenta corrumpuntur. In fativae
44 vero ficus pomis, haec animalcula nunquam inveni: num
44 vero ad haec volent ignoro ; fedulo hoc mihi inquirenti,
44 nullum fane in fativis ficubus apparuit. Neque enim Ita-
44 lia caprificationis indiget, fed fine groffis fativae ficus fua
44 coquunt poma. In Graecia hoc culturae opus perpetuum
44 non eft, ferotina poma non caprificantur; neque praeco-
44 ciorum in macro folo, et in aquilonio, in ipfa Graecia
ei ulla-fit caprificatio. Pomum caprificatum bonitate inferius
44 eft non capriftcato et infuavius, Hinc illi qui in Graecia
44 ficus
PHYSICAL and LITERARY. 259
bat does not fay that he tried them ; but in
general, that the date ftones of the French
iflands would not grow; and, it can fcarce be
fuppofed there were no males among all
their palm-trees . Befides many things con¬
cerning palm-trees , which appeared to be as
well attefted, are found to be vulgar errors.
But, granting that they really are barren ; this
may be owing to the climate, to the foil,
to bad culture, or to the want of Pontederd s
culices , rather than of the male duft, for any
thing yet appears.
39. Argu-
44 ficus venundabant, quo facilius emptores allicerent, «-
64 isplvccrcc iterum atque iterum clamitare folebant.” And?
after explaining the ufe of caprihcation, he adds, 44 Quare
44 concludendum, caprificationem in Graecia ob externas
44 C2ufas effe neceffariam, nequaquam ob ficus naturam, cum
44 alibi poma coquant non caprificata. Eadem etiam de
44 caufa palmas in quibufdam regionibus effe caprihcandas,
44 in aliis minime ; id autem per culices fieri, non vero per
44 affedionem, quam apices embryonibus communicent, fatis
“ demonhratum eh.” See Anthol. 1. 2. c. 34, and 35. p.
172, &c. Now fince M. Hegardt’s Cupid , or Miller does
not goe abroad, till well brufhed, and freed of the dull;
fince there is no caprification in Italy ; and fince, this
notwithftanding, he, and Linnaeus alfo affirm, 44 Ficus
44 in Hollandia quotannis prolici e feminibus, vel frijdu
44 lacerato terrae commendato, frudu tamen illo ex Italia al-
44 lato.” Amaen. Acad. 1. p. 233. Exam. Epicris. p. 16.
Sec ; I leave it to the reader to determine, whether caprifica¬
tion affords an argument for, or againft the fexes of plants.
s6o ESSAYS and OBSERVATIONS
39. Argument 7. Septimo jlores nu-
u tantes . Cum pollen mafculus, plerumque
cc acre fpecifice gravior, difficile furfum ten-
5C deret^ apud plerafque plantas, piftillum lon-
gius gerentes, florem nutantem fecit Crea¬
tor, ut ftigma eo melius attingat pulvis :
tc e. gr. in galantho, leucoio , cyclamine , narcif-
sc fo, fritillaria , campanula, erythronio , &c.”
Wahlborn (e), u Flores nut antes gaudent
cc piftillo, ftaminibus longiore, ut cadat pol-
u len in ftigma : campanula , leucoium , galan -
thus, fritillaria ft Linnaeus (f).
I readily grant, that the pollen mafculum,
or pulvis api cum, is heavier than air, it being
often heavier than water 5 and alfo, that fome
pores nutantes have the piftillum longer than
the Jlamina ; but cannot allow the reafon to
be gc ut cadat pollen in ftigma for thus it
mull fall on the back of the ftigma, when
the ft plus, is there thickeft 5 or fall by it quite,
when there flendereft and, in neither cafe,
can thus have ready accefs to the feed. Again,
in many genera of plants, not only in different
fpecies , but even on the fame ftem, fome
flowers hang down, others ftand eredt, o-
thers
{e) Amaen. aead. i. p. g^,
(/) Phil. Bot, p. 9 z.
PHYSICAL and LITERARY. 261
thers horizontal, while the piftillum and \ ft ami-
na bear the fame proportion to one another :
?.g. fome fpecies of the narciftus , campanulajili-
um, &c. And altho’ every ftos nutans had the//-.
ftillum longer than the ftamina , yet it could not
thence be inferred with any probability, that
the defign of the great Creator, in thus form¬
ing them, was what our authors allege, un-
lefs every eredt flower had its piftillum fhorter
than the ftamina, which is far from being
fabl, as is proven above (g). °
40. Argument 8. “ Videte et admire-
mini folertiam, quam Natura adhibet in
plantarum aquaticarum, quae farinam foe-
“ cundantem habent, floribus. Tempore
“ Aorefcentiae, flores fpecifice leviores reddin',
“ ultra acluae fuperficiem attolluntur, ut in
“ aifre foecundatio fiat, nec humiditate dilua-
tur gemtura . dum vero fub aqua flores ad-
huc reconduntur fuomerxi, fblicite per pe-
“ talorum commiffuras clauduntur, apicibus
!>! verfus ftigma inclinatis, et verfus interio-
t[ ra tantum farinaceis, exteriori fuperficie
membranacea et lata j ut in nymphea et
affinibus apparet, Gcjnerus (* h ) .
Octavo
{£) Vid. No 25.
(£) Differt. p. 9^
262 ESSAYS and OBSERVATIONS
<c Octavo fubmerji . Plantae haud paucae
« caule fub aqua latent ; inftante vero floref-
« centia, enatant flores, ut nympbaea , &c.
Aliae vero fub aqua omnibus fuis partibus
cc occultantur 5 ut myriophyllum , ftratiotes, po -
fiC tamogetones plerique, qui o tunes, fub fioref-
sc centia, fpicam floris fupra aquas exferunt,
« delude iter um ? perada florefcentia, de-
€C mergitur fpicaf Wahlbom (/).
« F/cm fubmerji adfcendunt fub florefcen¬
tia : nympbaea, fratiotes, myriophyllum, poiamo-
<c geton, hydrocharis, valifneriaf Linnaeus [k).
Although fome aquatic plants blow on¬
ly above the water, it cannot be proven that
all do fo : yea it is certain, that many fubma-
rine ones frudify under water. But, grant¬
ing all the alledged fads, it by no means fol¬
lows, that the defign of Nature is, to procure
the better accefs of the duft to the jligma ; but
rather that it may be difperfed in the air. For
fmce, under water, the flowers C€ folicite per
<c petalorum commifiuras clauduntur, apici-
cc bus verfus ftigma inclinatis, et verfus interim
cc ora tantum farinaceis f the duft, or its aura
feminalis , muft there have much eafier accefs
to
(?) Amaeri. acad. i. p. 96.
[k) PhiL Bot. p. 92.
PHYSICAL and LITERARY. 263
to the Jligma, than it can have, when the Jla-
mina are feparated, and expofed to the winds ;
efpecially, if it be true, as Mr. V aillant has it,
that, in hermaphrodite flowers, and fuch, ac¬
cording to the Sexualifts, is the nymphaea ,
and fome other aquatics, the duft is not
thrown out at once with fuch violence, as it
is where the fexes are feparated, <c fed adlum
generations (adds Mr .Gefner) floribus clau-
cc As exercent, dum ftigma ad hue intra me-
“ dias antheras eontinetur.” (/)
41. I mention thefe two learned authors,
t
tho’ I have the misfortune to differ from
them, not only becaufe they are commended by
Linnaeus , efpecially V aillant^ of whom he fays,
*c primus clare fexum expofuit (m), ” but alfo
that I may help them to a better in fiance,
than th eparietaria, of the fudden exploflon of
the dufl: of the apices in barren flowers : it is
the common flowering nettle , or urtica urens
maxima , B, p. 232. (n); for one cannot
obferve
(/) Vid. n. 2i. fupra.
(m) Bib. bot. p. 173.
(#) That is for a fpecimen of botanical fuperfluity ; urtica
foliis cordatis amends, cylindraceis, fexu diftin&is, mas , FI.
lap. p, 299 ; urtica foliis oblongo-cordatis, dioica, H. Cliff,
p. 440 ; urtica dioica foliis oblongo-cordatis, FI. fuec. p. 282 $
urtica maicula, Syft, Nat. 1335 urtica perennis, Amaen.
Acad. 2. 25. 99.
264 ESSAYS and OBSERVATIONS
obferve this flinging nettle for a few mi¬
nutes, in almoft any of the fummer months,
if the fun (hines, efpecially before noon, but
he muft fee many little clouds of duft, thrown
with a fort of explofion out of the burfting
apices , which foon difperfe and fail down.
This, however, being a iingle inftance, and
by me not obferved in fpinacia, mer amahs,
cannabis , or any fuch barren plant ; no ge¬
neral conclufion can be drawn from it.
42. Arg. 9. cc Nono, Syngenefia fruftranea.
c£ Flores compoftti variis modis fabricati funt.
« _ Polygamia fruftranea foeminis exfultat
“ maritatis, totum difeum occupantibus 5 flof-
« culi vero foeminei radium conflituentes, ob
« defedum fligmatis, abundante licet difei
«c pulvere, familiam propagare nequeunt,”
Wahlbom (0). I omit the reft, ftnee Livnczus
( ft) fays only, cc fyngenefta fruftranea: ubi
“ ftigma deeft, ibi nulla foecundatio : in ra~
dio centaureae , helianthi , rudbeckiae , corcc-
££ pftdisP But, in the radius or corona of all
thefe flowers, the flylus is alfo wanting, as
well as the ftigma, which may be many
ways
d
(0) Amaen. Acad. i. p, 96.
ip) Phil. Bot. p. 92.
PHYSICAL and LITERARY. 265
ways neceffary to the ripening the feed. It
does not therefore appear, that this proves or
confirms the foecundating virtue of the dufh
43. Argument 10. is a very extenflve
one. £t Ita fete in plantis habere didlitat de~
tc cimo omnium fiorum genuina conji deratio,
u Brevitatis caufa nonnullos tantum hie exa-
cc minare lubet,” Wablbom ( z ). And, for
brevity’s fake aifo, I fhall here pafs them all >
fome of them having been noticed already,
as others will be below ; with this obvious
note, that fuch a general pofition can be pro¬
ven only by an as general induction 3 which
is altogether impradicable.
44. But fince Malpighius , whom I reckon
one of the mod genuine contemplators of
flowers, obferves (a), that, cc Turgentibus
<c orbicularibus corporibus quibus ftaminum
{c capitula replentur, exjiccataque continent e
“ capfula , foras prodeunt globuli minimi et
“ difperguntur 5” and that this exficcation
does not, cannot well happen, before, by
opening of their covers, the Jlamina be ex-
pofed to the free air 3 and fince in fa the
L 1 apices
(2) Amaen, Acad. i. p. 97,
{a) P, 63. edit, in 4to,
266 ESSAYS and OBSERVATIONS
apices do not fplit, at leaft generally fpeak-
ing, fo far as I have obferved, until their co¬
vers open ; it appears to be a more natural
Inference, that this duft is not defigned to fall
on the Jligma , or to impregnate the feed {&).
And, confequently, that £C Omnium florum
££ genuina confideratio, nec diftitat, nec con-
££ firmat, generationem vegetabilium fieri1 J
in the manner the Sexualifis pretend.
45. Althg’ 1 have already, perhaps, been
too tedious, and faid enough to overturn the
modern do&rine of the fexes of plants 4 yet
there ftil-1 remain fome arguments for it,
which I cannot pafs. For Linnaeus fays, ££ An-
££ fheras effe plantarum genitalia mafculina , et
S£ earum pollen veram genituram , docet exTen-
*£ tia, praecedentia, fitus, tempus, locu-
C£ lamenta, caftratio, pollinis ftrudura : jii-
€£ gmata, germini uhique adnexa, zffzgeneta-
?£ lia foemimna, probat efifentia, praecedentia,
£C fitus, tempus, cafus, abfciffio (c)” Which
in Phil. Bot. (</), and Sponf. PI. (^), are ex¬
plained : but confirmed only, either by mis¬
takes, or by falfe conferences. Thus,
C£ Situs:
(b) Vid. No 40. fupra.
(c) Lin. Fund. Bot. § 143. 144,
(d) P. 90.
PHYSICAL and LITERARY. 267
<£ Situs : Didynamiftis ftamina adfcendunt
<£ fab corollae labrum fuperius, quo et fe pi-
<c ftillum fledtit.” Rut in the defcription of
his clafs 1 4. or didynamia , cc Antherae fob
££ labio fuperiore faepius reconditae” (/). And,
concerning the fitus, he adds, <£ Monaeciae
<c pleraeque flores ftamineos fupra piftilliferos
“ gerunt : zea, ricinusd But the flores fla~
minei are below the piflilliferi in ricinus .
What he fays of tempus , is anfwered above $
of caflratio , below : and what he obferves
of the loculamenta anther arum , and pollmis
JlruBura , teach nothing, but the author's
conjectures.
46. But, whether thefe arguments be
concluhve or not, caflratio florum molt cer¬
tainly demonftrates the ufe of the farina foe -
cundans , and confequently the fexes of plants ?
cc Veritatem hanc probat cajiratio. Si an the-
££ ras alicuhis plantae uniflorae auferamus, et,
€£ ne aliqua alia ejufdem fpeciei adfit, cure-
t£ mus j abortit frudtus, vel faltem ova profert
££ fubventanea 5 quod adeo certum, ut quif-
“ que nullo non fucceffu id expend queat,5>
Wahlbom(g ). l£ Caflratio : Melonis flores fta-
<c mineos
(/) Vid. Lin. Gen. pi. p. 261.
[g) Amaen. Acad. 1. p. 86.
?68 ESSAYS and OBSERVATIONS
<£ mineos qui diligenter auferunt, fruSus non
obtinent. Tulipae folitariae fi aurerantur
«e antherae ante cafum pollinis, flerilis eva-
tc det,” Linnaeus (b).
So the winds feem here to forget their du¬
ty. But, granting all here aliedged, it proves
nothing. For plucking off the petala may
have the fame effedl ; “ Saepius avullis flo-
ris foliis, antequam hiarent, in tulipa prae-
^ cipue, expedtavi an ftylus incrementa ca-
cc peret ; et interdum ejufdem incrementum
remorari obfervavi, quandoque quaedam
femina, abfque noxa, debitam fortita funt
magnitudinem,” Malpighius (i). Wounds
alfo in otherways neceffary parts, may be
the caufe of fuch barrennefs, by depriving
the feeds of their proper juices, &c. Never-
thelefs there is reafon to deny the fadt : for
furely M. Wahlbom did not make the experi¬
ment in every fpecies of flower's : M. Geof¬
freys mays ripened fome feeds, tho’ caftrated
(k) : and I made the trial in tulips, nulk
cum fuccejfu . Thus.,
(b) Phil. Eot. p. 90. and 92,
f/) Oper. p„ 70.
[h) Vid. Mem. Acad. 1 711.
47, One
PHYSICAL and LITERARY. 269
47. One year, obferving two ftrong tu¬
lips growing together, in an inclofure fur-
rounded with a tall and thick quickfet haw-*
thorn-hedge 3 I cut down two or three more
tulips y which Rood at fome diftance from
them, fo as to leave none within that inclo¬
fure, fave the two I mentioned : out of
thefe, gently opening the pet ala , I plucked
all the Jlamina with their apices ftili intire.
The confequences of this too rude caflration^
was a conliderable extravafation of the juices,
in the bottom of the flower, and a fudden
decay of the ovarium or fruit, which never
increafed, but turned yellow, fhrunk, and
withered. In order to difcover whether this
abortion was owing to the wounds, or to the
want of the dufl: of the apices 3 I fullered
thefe two tulips to remain in the place where
they were : and next Seafon, with the fame
precaution that no other tulips fhould flower
within the inclofure, I opened the pet a la ,
and took out carefully, not the jlamina , but
only all the apices 3 which prevented any fen^
Able bleeding of the parts. This more gen¬
tle caftration, they bore perfectly well 3 the
ovarium buffered nothin e. in either of them,
but
ESSAYS and OBSERVATIONS
but increased, and came to maturity, quite full
of feeds. See alfo Gardeners dictionary, ar¬
ticle generation , near the end.
48. Thus I think I have fufficiently an-
fwered all the arguments for the fexes of
plants, taken either from the ftrufture of
flowers, or experiments of any confequence
that I could meet wi ll. But fince no (mail
ftrefs feems ftill to be laid on the analogy be¬
tween plants and animals, as much favouring
this doctrine; I muft beg leave, a little to con-
lider it alfo, altho’ it is certainly true, to ufe
Mr. Needhams words ( /), that the method
of reafoning by analogy, is but too apt to lead
us into mi flakes ; and therefore we ought to
be very diffident of confequences deduced this
way : for mere analogy, founded on fadls,
and extended by conjecture, however plan-
lible, can, at moft, but furnifli motives for a
reafonable doubt, and further inquiry.
49. €£ Omne vivum ex ovo ; per confe-
• c quens etiam vegetabilia : ovum, non foe-
cundatum germinare, negat omnis experi-
cc entia; adeoque et ova vegetabilium,” Lin¬
naeus ( m ). I fhall not here enquire, whether ei¬
ther of thefe propofitions are certainly true ;
but
(/) Phil. Tranf. No 490.
(ffl) Fund. bot. § 132— 1 <roa
PHYSICAL and LITERARY. 271
but only notice, that they neither prove nor
explain any thing : for if omne vivum include
vegetables as well as animals, as certainly,
according to our author it does ; then he
might as well have faid, Omnia animalia et
*vegetabilia ex ovis , et per confequens etiam ve-
getabilia : if vivum do not include vegetables,
the confequence does not follow. The fame
holds in the fecond, and feveral others of
his aphorifms.
50. In how many things foever plants and
animals may agree, certainly they do not a-
gree in every thing. “ Ad fummum, (fays
“ cTheophraJlus') [n) non omnia fimiliter atque
“ in animalibus accipi debent : nam (in plan-
£C tarum genere) vis undique germinandi ha-
£C betur ; q.uoniam et undique animatum eft.’*
And Malpighius (0), C£ In vegetantibus, ubl
<c non eft tantus organorum apparatus, et
<c cuilibet fenfibili particulae, omnia infunt
<c quae in toto deprehenduntur : nulla inter ce -
denie generatione , abfciffi quicunque rami
<c frequenter in novam fobolem excrefcunt;
cc vel naturae minifterio, deciduae minimae
“ et compendiariae plantulae, a tenellis fur-
culis
( n ) Da hift. pl.l. i. c. i*
(0} Anat. pi. p. 76,
ESSAYS and OBSERVATIONS
272
cc culis fub feminum fpecie, propagationem
ouocimque anno perpetuant.” Hence ma¬
ny plants are much better and eafier propa¬
gated by cuttings, layers, offsets, gems or
buds, than by feeds : hence garlicks , onions ,
leeks , &c. carry gems frequently, on the top
of the ftalk, among, or in place of the feeds,
as well as at their roots under ground. What
are bulbuous roots but gems ? and fuch Caefal-
pinus obferved on the leaves of the moly ; as
they are frequently feen on the ftalks of tu¬
lips y lilies : and it is to buds that the increafe
of many trees is owing.
51. Now, what is a bud? how does it
differ from a feed ? “ Biffert foboles a femi-
4C ne, ut foetus vivens ab ovo ; femen enim
u tanquam ovum eft, in quo eft. principium
4 c vitale, at vita nequaquam; foboles autem
“ vivit, primo quidem juxta parentem, ut
“ ejus germen, poftea vero per feipfum, pro-
“ priis radicibus ex, terra humorem trahens,”
Caefalp . de plantis (p) : and Malpighius , (q)
44 Gemmae funt velut infans, feu foetus ita
cc cuftoditus, ut fuo tempore auftus, in fur-
culum exciefcens, tandem ova promat.
ec Erit
(p) Lib. 1. c. 5.
(?) Anat. Plant, p. 39. 77,
PHYSICAL and LITERARY. 273
£C Erit igitur probability* femen quafi gemma
££ pendula et decidua, alieno gerrninatura
tc foloA And although the learned Petrus
Lofling , in his treatife called Gemmae Arbo -
rum (r), or rather the publisher himfeif, is
pleafed to fay, ££ qui gemmam fibi reprefen-
££ tant ut alterum femen, fallunt et fallun-
£C tur” ( / ) ; yet his defcription of a gemma
feems not altogether to agree with this not an-
dum : for (/) he fays, ££ gemma eft pars plan-
££ tae radici iniidens, quae occultat fquamis,
56 foliorum rudimentis, embryonem futurae
£C herbae And below (u)i he explains what
he means by radix thus, “ Hae gemmae infi-
£C dent, vel radici fub terra reconditae, vel ra-
£C did fupra ter ram in truncum ramofum aJjur -
£C genti \ iliac, ubi carnofae fuerint atque mag-
££ nae, bulbi nomine veniunt, &c.” And elfe-
where (#), ££ Gemmam proinde concipio in-
£C ftar herbae in compendium redadlae, tedlae
£C et contra&ae fua inter extrema folia, ut ab
££ aeris injuria confervetur ; cui herbae nihil
Mm <£ amplius
(r) Amaen. Acad. 2. p. 182 224.
(/) P. 1 85. note k.
(/) P. 185.
( u ) P. 186.
(*) P. 192,
ESSAYS and OBSERVATIONS
27 4
“ amplius deeft, quam vis fe extendendi ; e-
fiC am autem calor demum excitatT Is not
this as applicable to feeds, as to gems ? tc Se¬
men, (fays Linnaeus ) (y) proprie, novum ve-
£C getabilis rudimentum, humore rigatum,
<c vefica tunicatum.” And is not a gemma
the fame ? or a more perfect feed ? however,
call it embryon , compendium, primordium plantae*
or what you pleafe, with its covers : lince
Linnaeus owns, <c Generationes plantarum ex
fe mine et gemma efie coevas (z) ; and “ gem-
mas , proinde ac femina , in fe continere pri-
cc mordium. plantae [a) f it comes to the
fame thing for our purpofe. For,
52, If gems contain the primordi a plantarum,
they contain the moft effential part of feeds
becaufe the feminis ejjentia conjiftit in corculo
(b) ; and the corculum is nothing but the
novae plantae primordium (c). Now fince
buds or gems are copioufly produced by
numberlefs plants, and often break out of
the fmootheft part of the bark, efpecially
of pruned trees 5 and, fince the fmalleft
part
(y) Lin. Phil. hot. p. 54,
(x) Phil. bot. p. 88.
(а) Gem. arb. Amaen acad. 2. p. iS^.
(б) Phil. bot. p. 56.
(c) Ib.p. 54.
PHYSICAL and LITERARY. 275
part of a plant may be made to grow and
emit gems, whether it be naturally fertile
or barren, male> female , or hermaphrodite :
does it not clearly follow, that neither dif¬
ference of fex, nor illapfus pollinis anthe -
rarum fupra figmata nuda , are neceflary to
the production of the primordia plant arum,
the efience of feeds, as well as of gems;
and that no imagined analogy between plants
and animals, can warrant or excufe the fulfom
and obfcene names, impofed by the Sexualifs
on the different parts of the fructification of
vegetables ( d ) ?
53. Not a few other arguments againft
the modern doCtrine of the fexes of plants,
might be brought from the ftruCture of ma¬
ny compleat flowers, as well as from the nu¬
merous tribes of fuch as are called lefs per¬
fect 5 fome of which produce feed, but want
flowers; others have neither flowers nor feed.
For it requires more than an ipfe dixit to
prove, that £C omnis fpecies vegetabilium flo-
“ re et fruCtu inftruitur, etiam ubi vifus eaf-
<c dem
[d) Vid Cl. Linnaei fundamenta botanica, § 140, 143,
144, et 146, and the learned commentaries on thefe, in the
Sponfalia pi ant arum, and Pbilofophia botanica ,
276 ESSAYS AND OBSERVATIONS
£C dem non affequitur/7 as Linnaeus afferts (^).
I know he attempts to prove it thus(/), cc Muf-
cc corum femina A7w ; lemnae flores delineati
€C a Vallifnerio-, fucorum flores obfervavit Reau-
iC mur ; pilulariae flores invefligavit B.JuJjiae-
cc us*, fungorum ftamina defcripfit Michelius ”
And this is all, and affords but a lame proof,
and mofliy conjedurah
Thus, although Dillenius (g), in the end
of a particular defcription of the felago foliis
et facie abieiis, R. fyn. p. 106. or upright
Jirr-mofs , fays, £< plura non obfervavi, nec
femina in his vel calycibus, vel foliis bra-
■ c deatis invenire potui:” yet becaufe he adds,
*£ Sufpicor autem bradeas illas folia femina-
<c ha effe, et novarum plantarum produdioni
cc infervire J the learned author of the Je¬
mma mufcorum (h), pofitively concludes,
Haec foliola, tempore autumnali matura de-
S£ cidunt a calyce perfiftente, et novam plan-
“ tarn propagant, radiculas e bafi exferentia”
Eut, fince below (/) he owns, that “ Semi-
€C na mufcorum tanquam nuda corcula, fine
£C cotyledonibus3
(e) Fund. bot. § 1 39.
(/) Phil, bot. p. 89. '
ig) Hid. Mufc. p. 437,
[b) Amaen. acad. p. 2. 295,
(d 299,
PHYSICAL and LITERARY.
2 77
cc cotyledonibus, fine tunicis animo concipi-
u enda funt. — Flos autem obfcure nobis per-
cc cipitur, cum nullum Jlylum , nullumque ftig -
cc ma habeat if, what he calls a feed, real¬
ly takes root and grows (for I find not that
either he or Dillenius made the experiment) j
it has a better claim to the character of a
gem, than of a feed. And, whether or not,
it is evident that the €C generatio mufcorum
<c minime fit, mediante pollinis antherarum
"c illapfu fupra ftigmata nuda.”
54. The fame learned author (k) afferts,
u Quod pulvis in capitulis mufcorum fit pol-
cc len mafculum:” that the “ femina lycopodii
“ officinarum, funtpurum putum pollen {/);”
tho? others think them all rather feeds. But,
whether they are either, I fhall not, can¬
not determine : only they feem to refemble
more the feed of the lingua cervina ; which
has been found fertile (m), without the foe¬
cundating influence of any antherae yet difco-
vered, that I know of. But, granting the
above cited aphorifm to be true in its largefi
extent, it can never prove the alledged ufe of
. the
(£) p. 300.
(/) p. 293.
(w) Vid. It. ox, 3. p. 555,
» 1 . ‘ 1 *
278 ESSAYS AND OBSERVATIONS
the duft of the apices in imperfedt plants,
where it does not appear 5 fince the contrary
is demonftrated in the moft perfedt of the
vegetable kingdom.
55. I noticed above, that feveral argu¬
ments might be taken from the fructification
of fome of the moft compleat plants : and
the author of the femina mufcorum ( n ) gives
fome inftances, and anfwers them ; how fa-
tisfyingly, I leave the reader to examine. On¬
ly, fince there are there three fpecies of the
viola, I fhall add a fourth, viz. viola martia
purpurea Jlore Jimpli ci odoroy B. p. 199. or com¬
mon March violet . This plant puts out its
flowers with the J lamina in March , on long
foot-ftalks; no fruit fucceeds them, nor ap¬
pears for fome weeks, yea months after, when
clofe on the root, and well covered with the
leaves, the fruit is formed, foon ripens, and
contains plenty of feeds; tho’ all the flowers
were plucked in March. Does either tempus
or proportion here confirm the fexual fcheme ?
56. Fo conclude ; Had the modern do¬
ctrine of the generation of plants, continued
only to influence the learned more accurately
£0
(«) P. 1 86, &c.
PHYSICAL and LITERARY. 279
to inquire into the ftrufture of vegetables, I
would never been at fo much pains to confute
it : but, fince it has given occalion to an in¬
tire deformation of botany, and to the in¬
troduction of an infinite number of new
names, and perplexing, tho’ childifh terms,
whereby this moll ufeful fcience, is like to be¬
come not only vaftly more difficult, but even
ridiculous; I thought it high time to publilh
fuch arguments as to me appeared fufficient,
by Tapping the foundation, to overturn this
hideous fuperilrudlure. For furely no me¬
thod at all, is much better, than fuch an one,
whofe nomenclature is more difficultly acqui¬
red, than the knowledge of the plants them-
felves, which alone is true botany. But of
tnis more elfewhere (c). It remains only
that we inquire a little into the real ufe of the
dull of the apices.
SECT. IV.
56. Authors are fo much divided in opi¬
nion, as to the primary ufe of this dull, that
it may be doubted whether it be of any to
the plant wffiich produces it. And, fince ve¬
getables ferve only, or at leaft chiefly, for the
ufe
M Tyrocin. Bot. I. p. 40. 50,
2> So ESSAYS an to OBSERVATIONS
nle of animals 3 what the great Mr. Boyle fays
of the one, may well be applied to the o-
ther (/>). And fince we fee bees frequent¬
ly come out of flowers loaded with their duft,
and apparently carrying it to their hives 3 it
is not improbable that they feed on it. For,
if Mr. Geoffrey s experiments can be depended
on (y), it cannot be the materia of wax, with¬
out being digefted and prepared in the in-
fed 5 and, how many other infedts may live
on it, I cannot telh
57. But*
{/>) “ The whole animal is but a part of that greater body
6t the univerfe ; and therefore cannot eafily be fuppofed to
e* have been framed and furnifhed with the parts it confifls
of, intirely for its own fake. And, when we fay, that all
“ its parts are contrived for the bed advantage for the animal,
“ I conceive it to be underdood in this limited fenfe, that
* the parts are excellently framed for the welfare of the ani-
mal, as far furtb as that welfare, is confident with the ge-
6i neral ends of the Author of nature, in the conftitution
<£ and government of the univerfe. All which ends it is not
ic an eafy talk to difeover, tho1 fome of them may be inve-
“ ftigable by us. And, it feems prefumption to fuppofe,
il that the welfare of particular animals, is any further de-
({ figned and provided for, than will confift with the cofrni-
“ cal ends of the univerfe, and the courfe of God’s general
providence, to which his fpecial or particular providence,
“ about this or that mere animal, ought, in reafon, to be
64 fubordinated.” Vid. Boyle’s Works, vol. 4. p. 548.
(?) Vid. Mem. acad. k. 1711.
PHYSICAL and LITERARY. 281
57. But, if it be infifted on, that its
primary ufe muft refpeft the plant itfelf :
perhaps Caefalpinus may be in the right, with
relation to the plants, whereof fome, in the
fame fpecies, carry /lamina , and others the
feed (r) : and Malpighius (/), and Tourne -
fort, with relation to fuch as bear both on
the fame individual plant : viz. that it carries
off what is excrementitious, and unfit for nou-
rifliing the feed ( t ). I own, indeed, that this
opinion does not well agree with that of
Caefalpinus, ; it being more than probable*
that the dull: of the apices , in barren as well
as fertile flowers, is of the fame nature, and
defigned for the fame ufe.
$8. And, from what has been obferved of
the parietaria , ficus^ viola , &c. yea and from
the general ftrudture of fertile, as well as bar¬
ren flowers ; it is adfo more than probable,
that this duft is rather excrementitious and
N n noxious
(r) Vid. fupra. N0 6,
( /) Vid. p. 70.
(/) “ Petala, '(fays Tournefort) alimentum a pediculo a c-
“ ceptum vifceris inftar, perficiunt, et fru&ui nafcenti fuppe-
“ ditant ; ineptis humoris partibus per ftamina, feu vafa ex-
“ cretoria, abeuntibus in apices feu receptacula Diximus
“jam apices, quicquid minus apti continet alimentum, in fe
“ recipere, rerumque valvas a congeitis excr emends deduci.”
Inft. p. 69 and 70,
2$2 ESSAYS AND OBSERVATIONS
noxious, than ufeful to the nourifhment, or
foecundity of the feed. Nor is this inconfi-
ftent with its influence, on the production
of the numberlefs varieties of new flowers^
which yearly adorn the gardens of the curi¬
ous : if the opinion, which has for fome time
prevailed, be well founded ; to wit, that it is
the beft way to obtain new varieties of fine
flowers, to plant near together fome of the
beft kinds of the fame fpecies, differently va¬
riegated, and fave their feeds : reckoning that
the dufts of thefe flowers have fuch influence
on one another, that their feed will produce
finer varieties, than the feed of the beft of
them would do, if it ftood alone, however o-
therwife managed. And on the fame foun¬
dation it is, that M. Du Hamel's fcheme, for
producing new varieties of fruits, is built («)„
I fay, allowing all this to be fac ft, which I
cannot confirm 5 it feems rather to eftablifh,
than to be an objection againft Mr. Tourne -
fort's opinion.
59. F or, lince all double flowers are mon-
fters, “ Luxuriantes fibres (fays Linnaeus)
“ nulli naturales, fed omnes monftra funt ;
5< pleni eunuchi evaferunt, proliferi monftro-
<c forum
{?/) Vid. Mem. acad. an. 1728.
PHYSICAL and LITERARY. 283
cc forum augent deformationem (a:)” j fince
the fined varieties of flowers are the mod
tender ; fince variegation of flowers, as well
as of leaves, is preternatural ; and fince even
the improvements of plants, or fruits by cul¬
ture, with relation to their ufefuinefs to us,
are but difeafes in the plants, confidered in
their natural date : may it not be properly in¬
ferred, that, whatever influence the dud of
the apices has in producing thefe, it mud be
owing to its noxious, not foecundating va¬
pours ?
60. And, to conclude, although it fhould
be granted that we have not fuflicient data, to
enable us to determine pofitively of what real
ufe this dud is to the plant : yet, fince it has
appeared, to a demondration, certain, that
fertile feeds may be produced without it ; our
ignorance herein, can never be an argument
of any confequence, for the modem fexual
fcheme, or dodrine of the fexes of vegeta¬
bles, againd which I have been arguing ;
with what fuccefs, I fubmit to the learned to
* *
determine.
(*) Fund. Bot. §150.
Art.
284 ESSAYS and OBSERVATIONS
Art. X.
'Remarks on chemical Solutions and Precipitated
ons , by Andrew Plummer, M. D . ;
Fellow of the Royal College oj Phyficians ,
and Profeffor of Medicine and Chemiftry in
the Univerfity of Edinburgh. *
THAT I may not give the firft in fiance
of breaking in upon the order and
rules eftablifhed in this fociety, I fhall lay be¬
fore you, at this time, fome mifcellaneous
obfervations, on the folutions and precipitati¬
ons which frequently occur in the profecuti-
pn of chemical enquiries.
I fhall lay down thefe remarks by way of
propofitions, and, after each, fhall mention
the fads or experiments which gave occafion
to the remark, or which confirm and illu-
Jlrate the propofition.
Although many of the in fiances which
I am to adduce, are common, and well
known to every one verfant in chemical ex¬
periments: yet, as the hiftory of chemical
folutions
V • . ‘ ‘-■ft V
f January 17 38,
PHYSICAL and LITERARY. 285
folutions is very extenflve, and as many An¬
gular conditions and appearances, are to be
obferved in the actions of various folvents,
upon the bodies which they diflfolve; it may
poffibly be of fome advantage, to any one
who (hall afterwards undertake to give a ra¬
tional and fatisfadtory account of the caufes
which produce fuch effedts, and of the laws
by which thefe caufes adt in particular cir-
cumftances, to have in his view a great ma¬
ny inferior axioms or canons, comprehend¬
ing as many particular inflances as poffible $
becaufe thefe may enable him to afcend to
more general canons; and at length to the
ultimate phyflcal caufe ; and again, from,
thence to explain the phcenomena> in particular
inflances.
By Jolution , is here meant, the feparation
and diviAon of a folid body, or of a thick
and confident mafs, by means of a fenfible
fluid, into parts fo fmall, as to difappear and
be equally difperfed through the fluid.
That liquor which makes the feparation
of parts, I call the fohent ; or, in the
Rile of the Chemifts, the menjlruum .
I muft take the liberty, to make one preli¬
minary remark, before I delcend to particur
Jars |
286 ESSAYS and OBSERVATIONS
lars : for, if the affertion of certain Chemifts
was well founded, it would, in a great mea-
fure, fuperfede any further enquiries.
I. The notion of an univerfal menflruum>
capable to diffolve equally every body to
which it is applied, appears repugnant to the
nature of things, and to thefe limited powers
which we difeover in all known bodies.
I (hall not undertake, in this place to ad¬
duce and examine the bold afiertions and
high pretenfions of fome Chemifts to the
difeovery of an univerfal folvent ; becaufe
it would exceed the limits which I propofe to
myfelf, and perhaps afford little entertain¬
ment or inftruftion. But I rnuft be allowed
to doubt of the pofiibility of an univerfal iol-
vent, until more certain evidences are produ¬
ced than what have hitherto appeared. For,
as there is a vaft variety of bodies which dif¬
fer much from one another in denfity, foli-
dity and texture, in the bulk, (hape and com-
pofttion of the conftituent particles, in the
degree of force with which thefe cohere a-
mong themfelves, and in the number, ftze,
and figure of the pores or interftices be¬
twixt the folid parts ; it is fcarce conceivable,
that
PHYSICAL and LITERARY. 287
■ that any one liquor can be endued with
powers correfponding to all the various cir-
cumftances of fiich a variety of bodies, fo as
indifcriminately to diffolve all : it is therefore
much more agreeable to the nature of things,
that there fhould be a variety of liquors en¬
dued with different qualities, in different de¬
grees, to feparate the particles of fo many
different folid bodies ; and daily experience
fufficiently confirms the truth of this conclu-
fion. There is perhaps no body, natural or
artificial, but there may be found a menjlruum
proper to diffolve it : and, tho’ fome liquors
are known to diffolve feveral bodies which
differ in many refpe&s ; yet even thefe fol-
vents, which are allowed to be mod: exten-
five, are found incapable of diffolving a great
many other bodies.
II. The denfity, folidity, hardnefs, fix-
ednefs and other manifeft qualities of bodies,
can afford us no certain mark or indication of
the qualities of the liquors, requifite to dif¬
folve them, if experience is wanting. Nei¬
ther can we conclude, from the (Length,
fharpnefs or corrofiver.efs of liquors, difco-
vered by their effeds on the human body,
the
288 ESSAYS and OBSERVATIONS
the fitnefs of fuch liquors to diffolve different
fub fiances.
Iron and copper, the hardeft of the metals,
which require the greateft force to extend
them, and the ftrongeft fire to bring them to
fufion, will be corroded and diflblved by li¬
quors moft harmlefs to the human body ; as
vinegar, juice of lemons, a folution of tar¬
tar, rhenifh wine, nay moift air : whereas
quick-filver, whofe particles are fo mobile,
eafily feparable and diffipated by a moderate
heat, and tin, which is very foft and eafily
melted, require more corrofive menftrua.
Coral, and fome of the hardeft gems, will be
better diffolved in a weak vegetable acid, than
in a much ftronger one of the mineral kind*
Oleum vitriolic fpiritus nitric or aqua fortis ,
the moft ponderous and corrofive of the a-
cid liquors, cannot diffolve bees- wax or crude
fulphur, which will readily relent in the
mild and foft oil of olives ; fal tartari , or 0-
kum tartari , p. d. is almoft equally corrofive,
with regard to the human body, as aquafortis :
yet the folvent powers of thefe liquors, with
refpedt to other fubftances, are moft oppo-
fite.
III. The
physical and Literary. 289
III. T he fitnefs of a liquor to diffolve a
certain body, cannot be certainly learned from
the agreement of that body in feverai pro¬
perties with another, which we know can
be diffolved in that liquor. Neither can
we fafely conclude, that two liquors, which
nearly referable one another, will mutually
diffolve all the fame bodies.
W e meet with abundance, of inftances, in
chemiflry, to make us cautious in drawing fuch
conclufions. Well redified fpirit of wine,
makes a very compleat folution of colophony
or any of the common rofins ; but there are
feverai fubftances which have a great affinity
to rod ns, as lacca, copal y amber , fulphur ,
which being digefted with highly redified
fpirit of wine, will fcarce give a tindure to
the fpirit ; that is, thefe bodies remain either
altogether, or, for the far greater part, indiffo-
iuble in that liquor, unlefs they are previouff
ly prepared and difpofed to a folution, by the
interpofition of another body, as a fixt alca-
line fait, &c. Deftilled vinegar will readily
diffolve -copper, lead, iron; but, it would
be rafh to conclude, that the fame liquor
will alfo diffolve gold, filver, antimony, what¬
ever agreement we find between thefe bodies
O Q afld
290 ESSAYS and OBSERVATIONS-
and the former. On the other hand, aqua
fortis and aqua regia appear to be much of the
fame nature ; and the former, by a very fmall
change, may be converted into the latter j
yea, further, they diffolve equally feveral
bodies, as copper, iron, fpelter, tinglafs :
yet, it would be erroneous to conclude, that,
whatfoever body one of thefe liquors dif-
folves, the other would diffolve the fame ;
for aqua fortis diffolves filver and not gold,
and, vice vcrfa , aqua regia diffolves gold and
not filver.
IV. The foivent power of fome liquors,
with refpedt to certain bodies, may be in-
creafed, diminifhed or deftroyed, by a very
fmall and almoft imperceptible change of the
liquors.
I put two grains of gold into a drachm of
fpiritus falis marini , and fet the glafs on warm
fand ; after fome hours, I could obferve no
fen fib! e change of the bits of gold, in colour
or bulk, nor of the liquor : then I put into
the glafs, as cautioufly as I could, one drop
of fpiritus nitric after fome time, I found
the liquor had affumed a bright yellow, or
goiden colour, and the gold quite difiblved ;
ioi there remained only a few white particles
PHYSICAL and LITERARY, 291
at the bottom, which were probably filver.
Thus the very fmall addition of fpiritus nitri
very much increafed the folvent power of the
fpiritus falls mar ini. It is known, that ole¬
um vitrioli poured on quick-ill ver, and kept
in the common air, or in a very gentle heat,
does not corrode or diffolve it ; but, if they
are brought to a heat exceeding that of boil¬
ing water, then the folution takes place. Mr.
Boyle teflifies, that, by his care to rectify or
dephlegmate aqua forth very much, he ren¬
dered it unfit to dififolve filver. While aqua
forth is diflfolving copper with a brifk motion,
if a little alcohol is poured in, the folution
will be ftopt.
V. Some bodies which we know can be
eafily diflolved in certain liquors, may be fo
changed by the fire, or otherways, that the
fame liquors will not afterwards diffolve
them. On the other hand, the fire renders
fome bodies fit to be difiolved in certain li¬
quors which could not be diflolved in them
before.
The oil of vitriol, as I faid before, alii fl¬
ed by a proper degree of heat, readily e-
nough difiolves quick-filver : but when quick-
fiiver is, by long digeftion in a moderate heat,
deprived
^92 ESSAYS and OBSERVATIONS
deprived of its fluidity, and turned into a red
calx , or has been firft diffolved in aqua forth ?
and afterwards, by evaporation and calcinati¬
on, freed from the acid, and reduced to a
red powder ; if either of thefe red powders,
I fay, is digefted with oil of vitriol, and made
to boil, this liquor will not now diflolve the
mercury, or fo much as change its colour.
On the other hand, tho y fpir.fal. mar . is not
efteemed a proper menjlruum of quick-filver
in the immerfive way, but when applied to it
in form of vapour in fublimation ; yet if this
fpirit is poured upon the red precipitate mer¬
cury, it prefently changes its colour to
white, and quickly diffolves it. Again, fpir*
jal. mar . readily diffolves clean and frefh fiie-
ings of iron : yet if thefe are frequently moifl>
ened with water, and by trituration and cal¬
cination turned to a crocus y fp. fal . mar . poured
upon this, raifes an effervefcence indeed, but
does not feem to make a folution; for the
iron lies at the bottom not fenfibly diminifhed
and the colour of the liquor is not changed.
Some ores, as they are taken from the mine,
tho’ they appear pretty rich and clean, yet will
pot readily diflolve in the fame menftrua ,
which are fit to diflolve the pure metals, un¬
til
PHYSICAL and LITERARY. 293
• til the ores are roafted, wafted and fmelted?
The calces of lead and tin will more eafily
diffolve in fpirit of vinegar, than the thin
plates or (havings of the fame metals.
VI. Some liquors which diffolve feveral
different bodies, while they perform the fo~
lutions, feem to adt in a different manner up¬
on each body, require different helps, and
diffolve different quantities of each.
This is very remarkable in the adtion of
oil of vitriol upon iron and quick- filver : to
make oil of vitriol diffolve iron fuccefsfully,
it muff be diluted with a quadruple quantity
of water; when the clean fiieings are put in¬
to this liquor by degrees, there arifes a ftrong
ebullition and effervefcence, with a confider-
able heat and thick (teams of a penetrating ful-
phurous fmell, which are apt to kindle and
make a fulminating noife upon the approach
of the flame of a candle ; and, laftly, one
ounce of oil of vitriol thus diluted will diffolve
an equal weight of pure fiieings of Reel : but,
when oil of vitriol is employed to diffolve
quick-filver0 it muff be ftrong and well de¬
phlegm ate d ; when it is poured upon the
quick-filver, it raifes no inteftine motion or
heat ; it does not begin to corrode or diffolve
the
294 ESSAYS and OBSERVATIONS
the quick-filver, till there is fuch a heat ap¬
plied, as will almoft bring the liquor to boil,
and even then the folution goes on flowly
and quietly : iaftly, to diffolve one ounce of
quick-filver, it requires, at lead, three ounces
of oil of vitriol ; and yet the quick-filver will
not he entirely fufpended in this ponderous
liquor.
Even water, tho* it diffolves all kinds of
falls, yet it does not adt upon all of them
with the fame eafe ; that is, the fame quan¬
tity of water cannot diffolve an equal quanti¬
ty of each fait, in the fame time, or with the
fame degree of heat 5 for an ounce of cold
water will foon diffolve half an ounce of
fait of tartar ; but half an ounce of crude
tartar cannot be diffolved in lefs than ten
ounces of water ; and that quantity of cold
water will make no folution until it is brought
to boil, and continues to boil for fome time,
new water being added to fupply the wafte.
Even that compound fait, made of the fixt
fait and chryftals of tartar, which, from its fo-
lubilify, with refpedt to common tartar, gets
the name of tartarus felubilis , requires little
lets than ten times its weight of warm wa¬
ter to diffolve it fully.
VII. Some
PHYSICAL and LITERARY. 29-5
. VII. Some bodies can be diffolved in li¬
quors of very different qualities, but in differ¬
ent proportions, with different helps, appear-
ances and effefts.
Common iulphur or its flowers diffolve
in any oil, but more eafily, and in greater
quantity, in a thick, mild, expreft oil, than
in a thin, hot, aromatic, diftilled oil. When
flowers ot fulphur are digested with oil of
olives, or lint-feed, it becomes a thick bal-
fam ; three ounces of oil will diffolve one
ounce of fulphur ; and any fmall part of ful¬
phur which remains, has the appearance of
melted fulphur. But when the flowers are
digefted with ethereal oil of turpentine, fix
ounces of oil will fcarce diffolve one of ful-
piiur, and what remains is not like the ful¬
phur in the former cafe 5 for, if the veffel
is cooicd gradually before the baliam is pour¬
ed off, the fulphur appears almoft like nitre
when it chryfiauizes, or a vegetating fait
branched out into long {lender ftalks. Sul-
phiu likeways diliolves in fpirit of hartfhorn,
but ftill in leis quantity, and with a fmaller
degree of neat. And it is to be obferved,
that the unrectified or oily fpirit will dif¬
folve more fulphur than the clear and pure
% /» * •
ipmt.
2 96 ESSAYS A^D OBSERVATIONS
fpirit. To make fulphor foluble in water or
fpirit of wine, it mu ft be melted, then mix¬
ed and incorporated with a fixed alcaline
fait, by which means it will moftly diffolve
in warm water, and give a deep and ftrong
tin dture to fpirit of wine.
The calx of lead, litharge or minium , dif¬
folve in diftilled vinegar ; but more fully and
quickly in aqua jortis diluted with fix
times its weight of water. The folution of
lead in fpirit of vinegar, being evaporated
ftowiy, to a due confidence, and then remo¬
ved to a cool place, never (hoots into fair di-
ftindt chryftals ; but thickens, as it Were,
into a faline niafs, like coarfe fugar, fome-
what moift ; and, with difficulty, can be
brought to a tolerable whitenefs : but the fo¬
ci
lution in diluted aquafortis , treated in the
fame manner, gives large, folid, finning
white chryftals, regularly lhaped. The calx
of lead or minium will like wife diffolve
by digefting or boiling in oil of olives or lint-
feed; but as it diftblves, it thickens into the
eonfiftence of an unguent or plaifter.
Good aquafortis or fpirit us nitri will dif¬
folve about an equal weight of quick- diver,
and the folution is performed with a great
commotion
PHYSICAL and LITERARY. 297
.commotion, heat, and thick red fmoke :
ftrong oil of vitriol diffolves fcarce a third part
of its weight of quick-filver, and the foliation
is made in a flow and imperceptible manner,
and requires the affiflance of a great exter-
nal heat.
The manner in which the acid of fea fait
is applied to quick-filver, in order to diffolve
and be united to it, is dill more extraordi¬
nary : there are two methods pradtifed, but
both depend on the fame principle, and pro¬
duce the fame effedt. For either the quick-
filver is rubbed in a marble mortar with green
vitriol calcined to whitenefs, decrepitate fea
fait, and a fmall proportion of dry falt-petre^
till the quick-filver is extinguifhed and dis¬
appears, this mafsisput into a fubliming glafs,
a gentle heat is made at firft, and gradually
increafed ; in the beginning strife white fleams*
if thefe are collected, they condenfe into a li¬
quor, which proves a weak aqua regia 5 then
there will fublime a white fhining ehryftal-
line body, which is a vitriol of quick-filver*
and goes under the name of mercurius f ublima -
tin corrojivus : that the quick-filver is here
diffolved by, and united to the acid of fea
fait, with a fmall quantity of the nitrous a-
P p £idb
2$S ESSAYS and OBSERVATIONS
cid, is evident, becaufe the fame materials*
without the addition of quick-filver, proper¬
ly treated, yield a good aqua regia which dif-
folves gold. Or quick-filver is firft diffolved
in aqua fortis , the folution is evaporated till
there remains a white, dry, vitriolic body*
which is to be mixed and rubbed with an
equal weight of decrepitate fea fait, and fu-
blimed as before : here like wife the acid of
fea fait, with a portion of the nitrous, is join¬
ed to the mercury \ for one way of prepa¬
ring an aqua regia , is by pouring aquafortis
upon decrepitate fea fait, and drawing off a
liquor by diflillation, which is in effedt done
in this cafe, only the acid incorporates with
the quick-filver into a vitriolic form.
VIII. The folvent powers of certai nmenfrua
are not deftroyed in the adt of folution, but
can be exerted on other bodies ; and the men -
ftrua feparated from the diffolved bodies, may
retain or recover all their former qualities.
This property of feverai folvents, will
be found to obtain* in many more inftances.
than is commonly imagined. Many folvents,
when they are adtually diifolving bodies, excite
a ifrong and remarkable effervefcence, with a
great expan fion, biffing, bubling, heat and
fmoke
PHYSICAL and LITERARY. 299
* fmoke ; and, after the folution, the liquors
frequently acquire new qualities which were
not confpicuous before, either in the folvents
or in the bodies diffolved : whence it is ge~
nerally imagined, that, from this ftruggle
or adfion and reaction betwixt the bo¬
dies, the particles of the menjiruum are
broken, their points blunted, and their fi¬
gures changed, by penetrating into the pores
of the folid body, by disjoining and dividing
the parts very minutely. But, I fliall en¬
deavour to make it appear, from experi¬
ments, that the adtive particles of mod: li¬
quors, employed as folvents, are extremely
tenacious of their figure, bulk and denfity,
at leaft of the powers and properties which
depend on thefe, and conftitute the particular
marks and characters of thefe liquors : that,
tho’ they have diffolved feveral different bo¬
dies, have entered into many competitions,
and have paft thro’ a great variety of forms ;
yet, after all, molt of them can be brought
back to their primitive ftate, and made to
exert the fame powers which they did at firft,
and again run thro’ all the fucceffive changes;
o o y
fo that it may be doubtful whether art can
intirely
*
JOO ESSAYS AND OBSERVATIONS
intirely change the nature of fome of thefe
folvent liquors.
To begin with fome familiar inftances to
confirm our remark. Water can diffolve a
certain quantity of any fait ; yet, when it is
fully impregnated with one fait, it will hill
diffolve a portion of another fait, tho’ not
fo much as the fame quantity of pure water
would do. From fea water, by evaporation and
<rfiryft alligation, are procured three diftindt
falts, befides other fubftances, as the ingeni¬
ous Mr. Brown has obferved, viz. the muria¬
tic, or fait for common ufe, the bitter pur¬
ging fait, and a fiery calcarious fait, different
from the other two ; yet fea water will
diffolve, at the fame time, a pretty confider-
able quantity of feveral other falts, as fugar,
fait ammoniac, fait petre and fait of tartar ;
and, after it has diffolved fufficiently of two
or more of thefe falts, it will, even then,
diffolve fome more fea fait, and ft ill more of
the epfom or Glauber s fait. Hence, by the
way, we find fuch a variety of mineral or
medicinal waters, impregnated in various
proportions, with' different falts, vitriols, me¬
tals, earths, &c. The acid of fea fait, which
has diffolved quick-filver, and chryftallized
with
PHYSICAL and LITERARY. 3oi
with it in the fublimation of corrofive mercu¬
ry, will diffolve the metallic or reguline part
of antimony into a liquor, called butyrum an -
timonii ; and this will afterwards diffolve
gold. Diffolve filver in aqua fortis> when the
folution is finifhed, add to it fome crude
fait ammoniac, in powder, and fet the vef-
fel in hot fand ; the filver will all fall to the
bottom : then pour the clear liquor into an¬
other glafs ; this will be found a good aqua
regia fit to diffolve gold, regulus antimonii ,
&c. There is another noted experiment
which evidently illuftrates and confirms the
remark. If fine copelled filver is diffolved
in proof aqua Jortis , and the folution is di¬
luted with an equal quantity of diftilled wa¬
ter ; it will continue clear and limpid, with¬
out any precipitation : if then a piece of po-
lifhed copper is put into the folution, the
filver falls gradually down, and the copper
is diffolved, as appears by the green colour
which the liquor acquires in a little time.
When the filver is all feparated, take out
the remaining copper, and put in a piece of
clean iron ; the green colour goes gradually
off*, by the copper falling down, and the i-
ron is diffolved in its place : after allowing a
fufficient
302 ESSAYS and OBSERVATIONS
fufficient time for the folution of the iron,
and precipitation of the copper, put into
the folution a piece of iime-ftone 3 the aqua
forth immediately works upon it with frefli
vigour : laftly, add fome fait of tartar, or
oleum tartari , p. d 3 this precipitates the Ro¬
ney matter, and renews the effervefcence.
This feems to finifh the work, and quite to
abforb the acid, and deftrov all its folvent
powers : yet even here the acid only lurks
and conceals itfelf by its ftridt union with an
oppofite fait. But art can again produce it to
view, and refiore all its former powers. If
in this procefs, live or fix ounces of fpir . ni¬
tric or aqua forth , were employed in the be¬
ginning, and, after the laft ftep, the liquor
is diluted with fome more water, ftrained
thro' brown paper, fully fatiated with the
alcaline liquor or fait, and then flowly eva¬
porated and chryftallized 3 there will be pro¬
cured a fait perfectly refembling common
falt-petre, in the fhape of the chryftals, ex-
plofive quality, and other marks. This, fa¬
ctitious falt-petre, then may be employed in
place of the common 3 and I diftilled fome
ounces of a fait, made much in the fame
way (for I imagine the intermediate fteps
will
PHYSICAL and LITERARY. 305
will make no alteration) with oil of vitriol, in
Glaubers manner, and obtained a ftrong
fmoking fpirit, which anfwers all the cha¬
racters of Glaubers fpirit of nitre, and diL
folves the fame bodies ; and therefore may
run thro’ the fame courfe, over and over,
without any change, unlefs that it may be
gradually wafted, lome part of it being dif-
iipated in every operation.
I found the fame thing hold in other acid
liquors, as fpirit of fea fait, fpirit of vinegar,
the acid of tartar, &c. which I joined to al-
caline falts, and recovered the acid by diftil-
lation. Thefe and fome other experiments
of the like nature, which I have not yet had
leifure to confider in their full extent, I fhall
take another opportunity to lay before the fo~
ciety. In the mean time I fhall proceed to
make fome
Remarks on Precipitation .
By precipitation is meant the parting or
feparating the fmall particles of a diffolved
body from the folvent liquor by means of a
third body folid or fluid, which is therefore
called the precipitant.
There
So4 ESSAYS and OBSERVATIONS
There is indeed another manner of part¬
ing the diffolved body from the folvent, which
is fometimes, tho’ lefs properly, called pre¬
cipitation 3 when, by drawing off part of
the folvent liquor by evaporation or diftilla-
tion, the diffolved body falls down gradual¬
ly in proportion to the quantity of the liquor
wafted,
I fhall chiefly confider the firft or more
proper precipitation, in which there is both
greater variety, and more difficulty to account
for the change.
Remark I. All precipitations do not hap¬
pen from the oppofition of an alcali to an acid 3
but there are different means of precipitating
different folutions.
It is certain, from experience, that what^
ever bodies are capable of being diftblved in a-
ny acid liquor, may be precipitated from it by
an alcaline fait or liquor. On the other hand*
any body that is diffolved in an alcaline li¬
quor may be parted from it by the addition
of an acid. This then is a pretty general'
method of precipitating : however this op-
pofition of acid and alcali is not the foie
caufe of precipitation 3 for many metals and
metallic
PHYSICAL and LITERARY. 305
I
metallic fubftances diflfolved in their proper
acid menflrua , may be precipitated by other
bodies that are not alcaline, fome by plain
water, fome by neutral falts, natural or arti¬
ficial 5 fome by another metal, fome by an¬
other acid liquor ; and, laftly, fome of thefe
folutions may be precipitated in two or three
different ways ; of all which I fhall give
inftances afterwards. But further, acid and
alcaline liquors are not the only folvents 5 for
water, ardent fpirits, oils, and feveral com¬
pound liquors, neither acid nor alcaline, dif-
folve a great many different bodies, which
likeways may be feparated from them by pre~
cipitants of diff erent qualities. Therefore an
acid and alcali do not always concur to make
a precipitation.
II. The weakening or diluting foliations,
by a liquor fpecifically lighter than the foh
vent, is not the foie caufe of precipitation.
Some who would account for precipitati¬
ons upon mechanical principles, contend
that diminifhing the fpecific gravity of the
folvent liquors is the caufe of all precipita¬
tions : but this, altho’ it obtains in fome in¬
ftances , yet, in many more, it will be found
contrary to experience. If" any fait is diffol-
3o6 ESSAYS and OBSERVATIONS
ved in water, and if fpirit of wine, a liquor
fpecifically lighter than water, is added to
the folution ; no precipitation will enfue.
When filver is diffolved in good aqua
jortis , the folution may be diluted with fair
water to any degree you pleafe ; yet the par¬
ticles of filver continue fufpended in the li¬
quor, tho? rendered fpecifically lighter :
whereas, when the thineft and lighted: parts
of the folvent are carried off by evaporation,
the filver falls down. In the fame manner,
a folution of quick-filver in aqua forth y a fo¬
lution of gold in aqua regia , of lead in fpirit
of vinegar, and fome other folutions of me¬
tallic fubftances, may be diluted with Ample
water without precipitation. Further, fome-
times a liquor fpecifically heavier than the
folvent is added to the folution, whereby the
fpecific gravity of the compound liquor is
increafed; yet the particles of the diffolved bo¬
dy are no longer fufpended in it, but fall to
the bottom, quite contrary to this hypothe¬
cs. Vv ben rofin of jalap is diffolved in high¬
ly rec lined fpirit of wine or alcohol , if water,
which is fpecifically heavier than the fpirit,
is poured in, the refinous particles can no
longer be lufiained. ihe fubiimate corrofive
mercury
O’
PHYSICAL and LITERARY. 307
* mercury can be diffolved in lime-water or
common water : upon pouring in oil of vitri¬
ol, a very ponderous acid liquor ; the mercu¬
ry lubfides. Coral diffolved in fpirit of vine¬
gar, will be thrown down by the fame oil
of vitriol. Thefe inftances naturally lead
us to another remark.
III. Some bodies diffolved in one acid li¬
quor may be precipitated by another acid.
To the two former examples of this man¬
ner of precipitation, I fhall add fome others.
Silver, diffolved in aqua forth , will be thrown
down, if fpir.fal. marini is put into the fo-
lution : on the other hand, a folution of gold
in aqua regia , fuffers a precipitation by the
affufion of fpir. nitri . That corrofive acid
liquor, called butyrum antimonii , is known
to be a folution of the metallic part of anti¬
mony in aqua regia : if we pour into it fpir.
nitric after a pretty flrong effervefcence, we
fhall find a metallic powder at the bottom.
IV. Some metals diffolved in an aad li¬
quor, may be precipitated thence by ano¬
ther metal or metallic, ftony or calcarious
fubftance, capable of being diflblved in the
fame menflruum .
Under
3o8 ESSAYS and OBSERVATIONS
i
Under the head of folution, I had occa-
fion to adduce a well known inftance, to
fbow that a menjlruum having diffolved one
body, will fucceffively diffolve feveral others
in a certain order. I am obliged to mention
the fame again, as a confirmation of the pre-
fent remark. If pure filver is diffolved in
proof aqua forth , and the folution diluted
with fair water; the filver will be precipitated
by copper, the diffolved copper by iron, and
that by lime-ftone. This however is not the
foie inftance of this way of precipitation : o-
thers may be found. The fublimate corro-
five mercury may be juftly looked upon as a
folution of quick-filver in the acid of fea
fait, or aqua regia, brought into a chryftalline
or vitriolic form by fublimation : when this
corrofive mercury is mixed with an equal
weight of common antimony, and thefe
rubbed together, left to moifien in the air,
and then diftiiled ; there happen fuch changes
to this mixture, as evidently fhow a real pre¬
cipitation of the quick-filver by the reguline
part of the antimony ; for the acid forfakes
the quick-filver, and diffolves the regains,
which makes the bitty rum antimonii : and the
•/ ’
gmck-filver freed from the acid, is by the fire
incorporated
PHYSICAL and LITERARY. 309
incorporated with the fulphur of antimony
into a black powder like /Ethiops miner alls,
which may be fublimed into the cinnabar is
antimonii . Quick-filver diffolved in aqua for -
tis, may likeways be precipitated by another
metallic body, as zink or bifmuth.
V. Some bodies diffolved in their proper
menjlrua , may be precipitated thence, by fe-
veral bodies of different qualities.
W e meet with a great many inffances in
chemiftry to confirm this remark. I (hall
mention a few examples, in which the great-
eft variety obtains. Pure filver being diffol¬
ved in good aqua forth , and the folution di-
ftributed into fix or eight glaffes, we may
make as many precipitations by different pre-
cipitants ; for folutions of fea fait and crude
fait ammoniac, fpirits of fea fait, vitriol and
fait ammoniac, a fixt alcaline fait, or its lee,
and a piece of copper, will, each of them
feparately, make a precipitation of the fil¬
ver.
Quick-silver diffolved in aqua fortis ,
may be precipitated by a folution of fea fait,
by a folution of crude fait ammoniac, by
frefh urine, by fpirit of fait ammoniac, by
oL tart » p. d. and by zink.
P^EGULUS
po ESSAYS AND OBSERVATIONS
Regulus of antimony diffolved in aqua re -
gia, will be precipitated by plain water, by
a folution of falt-petre, by fpirit of nitre,
and, by the alcaline liquors, fixt and vola¬
tile.
VI. The matters precipitated from the
fame folution, by different precipitants, dif¬
fer from one another in feveral remarkable
qualities.
When either a muria of fea fait, a foluti¬
on of fait ammoniac, or fpirit of fea fait (for
thefe three have nearly the fame effedts) is
put into a folution of filver ; it becomes milky,
and, as it were, cruddled, and, at length,
a white powder fubfides to the bottom : this
powder being wafhed with warm water and
dried, is foft and impalpable 5 its weight ex¬
ceeds that of the filver diflolved, by more
than one fixth part. This powder comes
much fooner to fufion than filver, but does
not recover the appearance or properties of
that metal ; for it looks like a piece of yel-
lowifh glafs, fe mi-opaque and brittle, yet
bending or yielding a little, whence it gets
the name of luna cornea , or horny filver ; and
it is with great difficulty that it can be reduced
to true malleable and dudtile filver.
When
\
PHYSICAL and LITERARY. 311
When a plate of copper is put into a folu-*
lion of Elver diluted, the furface of the cop¬
per is immediately covered, as it were, with
a coat of Elver ; this becomes gradually
thicker, and appears tufted, fpungy and loofe :
upon fhaking the plate, large pieces of this
cruft falls off, which either rife to the top,
or fwim about in the liquor for a while, till
difcharging many bubbles of air, they grow
heavier, and fall down in form of a white
powder ; the Elver being in this manner fe-
parated from the liquor, then walked and
dried, is nearly of the fame weight with
the Elver diffolved ; and, when melted, runs
into a lump of pure malleable Elver, without
any confiderable lofs.
If an alcaline liquor, as fpir . fal. ammoni -
&ci , or cl. tartari p. d. is dropt into a folution
of Elver, it excites a ffrong effervefcence,
which will be renewed when more of the al-
caline liquor is dropt in at intervals, until the
acid is fatiated ; and there appears a white,
bulky and frothy matter, which gradually
fubfides : all being thrown into a cap of
brown paper, fitted to a funnel, and warm
water poured in, the frothy matter diminifhes
confiderably in bulk 3 and there is left a
gi2 ESSAYS AND OBSERVATIONS
powder of an aih colour, which being dried,
a little exceeds the weight of the Elver dif-
folved.
The precipitations of mercury (hew ftiil
a greater variety, at lead, as to their effects,
being ufed as medicines. If fea fait, diffol-
ved in a good quantity of water, is put
into a folution of quick- filver in aqua forth >
it turns the clear and limpid folution turbid,
opaque and milky ; at length the white mat-
ter fubfides, which being feparated from the
fluid, waflied and dried, remains a very white
powder, and a little exceeds the weight of
the quick-fliver diffoived : but it is to be ob«
ferved, that the muria does not precipitate all
the mercury ; for the liquor, thus feparated
from the white powder, is known to have the
effedts of a cofmetic or deterflve mercurial
water 5 befides if oL tart . p. d. is dropt into this
liquor, a fmall quantity of a brown mercurial
powder will be precipitated. Phyficians know
that this white precipitate is a pretty adtive
and brilk medicine, and produces greater ef-
fedls, even in a fmaller dofe, than calomel ,
but is more mild and tradrable than the mere 4
fuhlim . corrojhus ; for, when this laft is fome^
what tempered by fpir . faL ammoru it be¬
comes1
PHYSICAL and LITERARY. 313
comes a medicine much of the fame nature
with the preceeding white precipitate. A fo¬
liation of crude fait ammoniac, and fpir. JaL
mar. have the fame effefts on the foliition of
quick- (liver, as the muria has*
If a little frefh urine is put into a folution
of quick-filver in aqua portis , there will like-
wife happen a precipitation 3 but the powder
is not white, but of a pink or fiefhy colour,
it appears pretty bulky, and has acquired a
little additional weight. This precipitate is
not ufually prefcribed by phyficians 5 but M.
Lemery pretends that it is milder than the:
white, and only operates by (tool.
It would appear then, that, in many in-^ *
fiances of precipitation, the particles of the
diffolved body are increafed in denfity and
fpecific gravity 3 by reafon that feme parts ei¬
ther of the precipitating matter only, or of
the compound, made up of the fclvent and
precipitant, are very firmly united to them,
fe that they cannot longer be fuftained in the
liquor. But, in other cafes, where the
matter precipitated has acquired no addition
of weight, no new or remarkable properties*
and is eafily reducible to the native form of
the body diffolved 3 there muff be feme o-
R r
3i4 ESSAYS and OBSERVATIONS
ther caffe of precipitation, which may pro¬
bably be, that there is a greater affinity betwixt
the precipitating body and the folvent, than
betwixt this and the body diffolved ; whence,
from the difpofition of thefe bodies to unite,
they fhake off, or drive away from them,
the particles already joined to the folvent.
Art.
PHYSICAL and LITERARY. 315
Art. XL
Experiments on Neutral Salts , compounded of dif¬
ferent acid Liquors , and alcaline Salts, fixt
and volatile ; by the fame.
T a former meeting of the fociety
A ( January 1738) I read fome re¬
marks on chemical folutions; the laid of
which gave me occafion to mention fome ex¬
periments, in which I was then employed,
but had not finifhed : and therefore, at that
time, I could not confider them in their full
extent, or have a juft view of all the confe-
quences that might be drawn from them.
I now proceed to relate the experiments,
and to obferve how far they may be uieful to
extend our knowledge.
I prepared a parcel of fa&itious, or (as
the Chemifts are pleafed to call it) regenera¬
ted nitre, in this manner 5 I took two ounces
of an extemporaneous fixed alcaline fait,
made of equal parts of nitre and tartar ; I
diffolved
* June 7. 1739.
&
JI 6 ESSAYS AND OBSERVATIONS
diflolved this fait in warm water, filtred th
folution, and poured into it ftrong fpirit of
nitre, a little at a time, until the alcaline li¬
quor was perfectly fatiated with the acid,
which required one ounce and a half of the
fpirit of nitre. From this faline liquor, by
evaporation and chryftallization, I procured
two ounces and a half of fait, when it was
all colleded and well dried. The chryftals
were long, flender and prifmatical ; the fait
had a pretty mild and cooling tafte ; and bits
of it put upon a burning coal, made it fpar-
kle and give a bright flame.
We may obferve by the way, that the
compound fait exceeded the weight of the
fixed fait by half an ounce or 240 grains ;
this additional weight it procured from the
fpirit of nitre : therefore one ounce and a
half, or 720 grains of the fpirit of nitre
which I ufed, contain 240 grains of true a-
cid, which is capable to fatiate four times
its weight of alcaline fixt fait.
I put two ounces and a half of this facti¬
tious nitre into a fmall glafs retort, and pour-
pd upon it one ounce of oil of vitriol, which
immediately begun to raife an ebullition with
peat and red fumes ; a receiver was inftantlv
joined
PHYSICAL and LITERARY. 317
joined to the retort with pafte 5 the glafs
fet in a fand furnace, and the fire increafed
gradually. After the operation, there was
found in the receiver, a fmoaking acid liquor,
of an orange colour, which weighed one
ounce, two drams, three grains : there re¬
mained at the bottom of the retort, a cake
of white folid fait ; which being diffoived in
warm water, the folution filtered, and part
of the water again exhaled, fhot into chry-
ftals ; and thefe being all carefully collected,
weighed two ounces, twenty two grains.
The fpirit obtained in this manner was
fiery, aftive, and conflantly emitting red
fumes ; it diffoived filver, kindled with oil
of cloves, and agreed in all other char afters
with ftrong fpirit of nitre. The fait which
remained in the retort when purified and
chryftallized, no way refembled falt-petre,
or the fait employed in this operation, in the
fhape of the chryfials, tafte, or other pro¬
perties ; for thefe chryfials were polyhedras,
having feveral triangular faces and folid
angles ; their tafte is rough, bitter, and
fomewhat aftringent ; they do not readily
melt or fparkle in the fire, as common or
faftitious nitre does.
3i$ ESSAYS AND OBSERVATIONS
I made another factitious fait, by impreg¬
nating a folution of the fame alcaline fixt fait
with fpirit of fea fait, pouring it in by
degrees, till there appeared no effervefcence3
and the liquor tafced briny. Four ounces
and a half of this fpirit were employed to
fatiate two ounces of the fixt fait : when the
two faline liquors were duly proportioned,
there appeared, before evaporation, a great
many fmall grains of white fait at the bottom,
which, as well as the liquor furrounding
them, had the true muriatic tafte.
The fait obtained out of this liquor, had
the genuine figure of the common fea fait ;
but the chryftals were fmaller, more hard,
white and opaque : the fait is not altogether
fo pungent as what we commonly ufe ; but
more agreeable and cooling, yet without any
acidity. This fait, while moift, weighed
two ounces, fix drams and a half $ but, when
well dried, and flightly decrepitate, the
weight was reduced to two ounces and two
drams. I put this quantity of powdered fait
into a fmall glafs retort, and poured upon it
two ounces of ftrong fpirit of nitre, which
occafioned an ebullition with heat and finoke.
«
I proceeded to the diftillation, with a fire gra-
PHYSICAL and LITERARY. 319
dually increafed ; when the veffels were cool¬
ed, I found in the receiver, two ounces four
drams and a half, of an acid liquor, of a
faint greenifh colour, which fmoked much
when the veffels were firft disjoined ; but the
fumes were paler and whiter than thofe of
fpirit of nitre, and fooner ceafed, I put a
few drops of this liquor into a folution of fil-
ver in aqua fortts\ it made it white and crud-
dled, and at length a white powder fell down.
I poured a fmall quantity of it upon a few
grains of filings of gold; with the affiftance
of a little heat, the fpirit pretty quickly dif-
folved it, leaving only a few particles at the
bottom. From thefe characters I think we
may conclude, that the acid liquor, produ¬
ced in this operation, is a true aqua regia :
I chufe rather to call it fo, than fpirit of fea
fait ; becaufe I found it had a greater and
quicker effeCt in diffolving gold than the plain
fpirit of fait had, therefore it is probable,
that a fmall quantity of the nitrous acid had
accompanied the acid of fea fait.
The ke remained in the retort, a cake of fo¬
lk! white fait, like melted nitre, or fal prunel-
iae : after it had been diffolved in warm
water, the folution filtered and evaporated j
there
426 ESSAYS ANO OBSERVATIONS
there appeared many regularly fhaped chry¬
ftals, long, Header, and prifmatical, of the
nitrous kind 5 which being removed, and
more of the moifture exhaled, the chry ftals
which formed were not fo large nor fo regu¬
larly fhaped as the preceeding, but the whole
appeared like a mafs of white fait coarfely
powdered : however I could difcover, among
thefe chryftals, fome that had a quadrangu¬
lar bafe, but long fides, like two cubes joined^
others varioufly compounded or broken : e-
ven this part of the fait had the cooling
nitrous tafte ; and, part of it put upon a.
live-coal, fparkled and excited a bright flame
like falt-petre.
Again, I took two ounces of that neutral
fait, called tartarus folubilis , the preparation
of which is very well known ; in this com-
pofition, the native acid of white tartar, or the
chryftals of tartar, is impregnated with an
alcaline ley, or oh tart.p . d . from the union
of thefe in due proportion, arifes a mild
neutral fait, which diffolves more eafily in
water, than tartar or its chryftals ; whence
it hath the epithet of foluble. I put two
ounces of this preparation into a fro all glafs
retort, and poured upon it one ounce of oil of
PHYSICAL and LITERARY. 321
vitriol, which raifed a babbling and efferves¬
cence. In diftillation there came over fix
drachms of liquor, of a brownifh colour, with
a little oilinefs upon it : its tafie was fowre, but
difagreeable and empyreumatic ; it had an un-
pleafant fmeil, but not very ftrong or pun-
gen t ; it effervefced with alcaline falts fixt or
volatile : in all which properties it agrees with
the acid liquor drawn by diftillation from
crude tartar, which is commonly called its
jplrit . I obferved, in diftilling this mixture,
that there came up fome volatile fait, but in
very fmall quantity, which fpread itfelf upon
the neck of the retort, in very fine and fub-
tile ramifications : the upper part of the bo¬
dy of the retort was fullied with fome thick
black oil ; and the faline matter at the bottom
was of a dirty afh colour, like tartar half-burnt.
I poured warm water into the retort, and
left it on hot fand, to diffolve the fait ; I found
it neceffarv to pafs this folution through a
filter, and there remained in the paper a good
deal of black earthy matter. The liquor was
very acid, and had a vitriolic roughnefs,
becaufe more oil of vitriol had been poured
upon the tartarus folubilis than was fufficient :
to overcome the acidity, I dropt into the li-
S s quor
322 ESSAYS AND OBSERVATIONS
quor fome oL tart . p . d. till the effervefcence
ceafed ; and then, by evaporation and chry-
ftallization, I procured a fait, in every refped:3
like the tart arm vitriolatus , as ufually pre-
Upon two ounces of the fame tart.folubih
I poured one ounce of fpirit of fea fait, made
after Glaubers manner ; by diftillation there
was produced a liquor of the fame kind, with
that of the preceeding experiment. The re¬
maining fait indeed was not diffolved nor
chryftallized ; but from its tafle, and by its
precipitating a folution of fiiver in aq. fort .
it appeared to be of the muriatic kind.
After this, I made an experiment on an¬
other neutral fait in which the acid of vine¬
gar is united to the alcaline fait of tartar,
which is commonly known by the name of
tartarus regeneratus. I took one ounce and
an half of fait of tartar, and poured diflil-
led vinegar upon the dry fait at feveral times,
fhaking the glafs frequently, till fifteen oun¬
ces of the acid were employed : the veffei
was then let on a fand- bath, and the liquor
gradually infpitTated till there rema’ned four
ounces 27 grains of a moift, greafy, fa line
fuoftance, of a brownifh colour, like coarie
‘ fugar.
PHYSIC AL and LITERARY.
323
fugar. I did not think it for my prefent
purpofe to bellow more time and pains to
bring this fait to a greater degree of white-
nefs and drynefs ; but l put it into a retort*
and poured upon it one ounce and an half
of oil of vitriol, diluted with three ounces of
water : in diflillation there came over near
feven ounces of a thin limpid acid liquor,
which, in talle, refembled diftilied vinegar,
but was more ftrong. The faline mafs left
in the retort being diffolved in warm water,
the folution filtred and evaporated, the chry-
ilals could not be diflinguilhed from the or¬
dinary tartarus vitriolatus in fhape, colour,
or talle.
To fatisfy myfelf, that a volatile aicaline
fait or fpirit may like wife be difengaged from
an acid to which it has been united, and re-
ftored to its former llrength & qualities, 1
made the following experiment. I took eight
ounces of that compound faline liquor, which
is defcribed in our College* difpenfatory un¬
der the title of Spiritus Mindereri ; it is made
by pouring diftilied vinegar upon volatile
fal-ammoniac, until the fait is diffolved and
fatiated by the acid. This neutral faline li¬
quor, however, will not chryftallize or co¬
ale fee
324 ESSAYS and OBSERVATIONS
alefce into a dry folid fait, nor will the vo¬
latile alcali feparate from the acid, by a Am¬
ple diftillation, but they rife together. I put
eight ounces of this fpirit into a bolt-head ;
and, adding half an ounce of dry fait of
tartar, I prefently fitted a capitel and recei¬
ver to the body, luted the joinings, and fet
the veffels in a fand heat ; in a little time a
white volatile fait fublimed into the capitel,
which was foon wafhcd down by a watery
vapour into the receiver. This liquor being
tried, was found equally ftrong, pungent,
clear and volatile, as the heft fpirit of fal-
ammoniac : the faline matter left in the bo¬
dy was of a greyifh colour, foft and greafy
to the touch, and would hardly dry or chry-
ftalhze, refembling tartarus regeneratus .
I need not confirm this by any further ex¬
periment, becaufe it is known to every body,
that the volatile fait and fpirit of fal-ammo-
niac are procured by adding a fixt alcaline
fait to the crude fal -ammoniac : now, as we
can prepare an extemporaneous or artificial
fait, by impregnating the volatile fait or fpi¬
rit of fal-ammoniac with the fpirit of fea. fait ;
j/V P ftav e no reafon to doubt, but, by means
of
PHYSICAL and LITERARY. 325
of a fixt alcaline fait, we may again difen-
gage the volatile fait or fpirit from the acid.
But it may be of more importance to dis¬
cover what kind of acid is oined to the vola-
j
tile alcali in the common or crude fal-ammo-
niac: for this purpofe I made the following
experiment. When all the volatile fait and
fpirit are drawn off* from crude fal-ammoniac
by the addition of a fixt alcaline fait and wa¬
ter, there remains a faline mafs ; which,
when diflfolved in warm water, the folution
ftrained and evaporated, the chryftals very
much refemble thofe of fea fait, in Ihape,
tafte, and other diftinguifhing characters of
that fait, efpecially when it is well depurated
and carefully chryflallized. This fait, how¬
ever, has been dignified with the title of
fal jebrifugum Sylvii . I put three ounces of
it into a retort, and poured in one ounce of
oil of vitriol, and as much water. In the
aiftillation, the receiver was filled with white
fumes, which condenfed into a liquor of a
pale colour, fomewhat turbid at firft, of
which I had near three ounces. The liquor
had all the appearances of the fpirit diftilled
in Glauber s manner, from common fea fait ;
and when fome of it was dropt into the folu-
tions
22 6 ESSAYS AND OBSERVATIONS
tions both of filver and quick-ftiver, it
turned them both milky, and made a white
precipitation. From all which I have no dif¬
ficulty to conclude, that the acid contained
in crude fal-ammoniac is of the muriatic kind,
or the fame which is produced from fea fait.
But, whence this acid fhould proceed, is a
matter of greater intricacy ; fince we are af-
fured that no fea fait is neceflary to, nor em¬
ployed in, the preparation of that fal-ammo¬
niac which is brought to us from Egypt .
This queftion 1 fhall not undertake to dif-
cufs, as being foreign to my prefent purpofe $
but fhall fubjoin fome remarks on the experi¬
ments above related, or deduce fome corol¬
laries which feem naturally to arife from
them.
I. The acid fpirits, as thofe of vitriol, ni¬
tre, fea fait, vinegar, &c. are faline liquors,
or fluid falts, made up of the very minute
particles of an acid fait, and a certain pro¬
portion ol phlegm or water.
II. The particles of thefe acid falts cannot
be brought to unite, among themfelves, by
chryftallization or fublimation, fo as to ap¬
pear in the form of a folid or dry fait : but
they
I
PHYSICAL and LITERARY. 327
they readily lay hold on the particles of cer¬
tain metals or femi- metals, calcarious or ab-
forbent earths, or oppofite falts, fixt or vo¬
latile, which ferve them as a bafis ; and*
joined to thefe, they aflame a chryftalline
form.
III. When any of the acid liquors are
joined, in due proportion, to any alcaline
fait, whether fixt or volatile ; the particular
acrimony and pungency of both, as to our
fenfes, and their power of diflolving certain
bodies, in a feparate ftate, are quite deftroy-
ed, at leaft, overcome and fufpended, by
their union.
IV. When an acid liquor has difiblved a
metallic body, and is united to it 5 the folution
and the vitriol made of it, are frequently
more acrid and corrofive, with refpeft to the
human body, than the acid by itfelf. I do
not affirm this univerfally: but we have in~
ftances of it in the folutions and vitriols of
filver, quick-filver, copper, antimony.
V. When the fpirits of nitre or fea fait
are joined to fait of tartar, or pot-a(h, and
chryftallized ; the chryftals aflame the pecu¬
liar fhape, and mo ft remarkable properties
cl the natural ialt, from which the acid fpi-
rit
]
*
328 ESSAYS and OBSERVATIONS
rit was originally produced. Confequently -
there appears to be fome affinity betwixt the
native fixt bafes of thefe falts, and the fixt
falts of plants.
VI. The artificial vitriols compounded of
the fame acid fpirits and metallic particles,
do not referable the original falts ; but the
vitriols of different metals, or metallic bo¬
dies, have different fhapes, tho’ they are join¬
ed to the fame acid falts.
VII. The acid falls, tho’ combined with
the alcaline, into mild neutral falts, yet are
not fo changed by this union but, when they
are again artfully disjoined, they may exert
the fame powers and produce the fame ef-
fedts as before their union : therefore we may
conclude, that the figure, bulk, and denfity
of the acid particles are not changed tho*
the liquors may differ fomewhat in ftrength
*
from the greater or fmaller proportion of
phlegm, or water accompanying the real a-
cid.
VIII. One acid which has been united to
an alcaline fait may be fet at liberty, or ex¬
pelled from its cohefion with the alcaline
Talt, by another acid of a different origin.
But this does not happen indifcriminately ;
for
PHYSICAL and LITERARY, 329
for the oil of vitriol expels any other acid,
but cannot be diflodged by any of the reft,,
A volatile alcaline fait is expelled from its
union with an acid, by a fixt alcaline, but not
contrary ways.'
General Scholium .
We can have no other idea of a folid or
confident body in general, as diftinguifhed
from a fluid, than that the parts of a folid
cohere together by fome power, which re¬
tains the particles in their fituations, with re-
fpedt to one another, and makes them to
relift their feparation or divifion, till that
power is overcome by a fuperior force.
When we obferve that a certain fluid, as
water, poured upon a hard folid body, as a
lump of falt-petre, in fome hours, makes
fuch a change upon the lump, that it whol¬
ly difappears, if the glafs is fliaken a little,
that is, the fait is divided into particles, fo
imall, that they efcape our fight, and are
equally diftributed through the liquor, and
fufpended in it 5 when we obferve this, I fay*
we cannot but conclude, that the particles of
T t Water
ESSAYS and OBSERVATIONS
33°
water are endued with a power capable to o-
vercome the force by which the particles of
falt-petre cohered with one another.
If a known quantity of cold water has
diffolved as much falt-petre as it is capable to
hold, in this folution the water is to the fait
as O to i ; (in Raiding water the pro¬
portion is as 4 to i ). If then f of the wa¬
ter is wailed by evaporation, many of the
frnali particles of nitre being brought into
contact, join together, and form chryftals in
fhape and other properties refembling the
nitre which was diffolved in the water. It
follows, therefore, that the particles of nitre
mutually attract one another, when the inter-
pofing matter is removed, the diftance betwixt
them very much dim in iff ed, and no fuperior
power acting upon them 5 and, when in
contact, they cohere with a certain degree
of force. Again, it appears, that the par¬
ticles of water do attract the particles of nitre
more ftrongly than thefe laft attract one ano¬
ther ; and, confequently, overcome their
coheiion, and fufpend their mutual attraction.
Laftly, it is evident, from the above appear¬
ances, that tho’ the parts of nitre which
fwim in the water are fo fmall, that they
are
PHYSICAL and LITERARY. 331
are not perceptible fingly, even when viewed
thro’ a pretty good lens ; yet they mu ft be
fimilar to one another, and retain the proper¬
ties of real nitre.
Let us next confider the effects of an¬
other liquor, upon the fame falt-petre.
If oil of vitriol is poured upon a parcel
of nitre, there happens like wife a folution,
but with appearances different from thofe in
the former 5 for this is accompanied with a
confiderable inteftine motion and expansion,
fmoak and heat, and produces a much great¬
er change on the nitre *: for, by the help of
external heat and ciofe veffels, there rife
from the mixture copious red fleams, which
are condenfed into a corrofive acid liquor, ve¬
ry active and volatile, and there is left a
white faline mafs, no way refembling nitre.
From what has been faid formerly of
this experiment, it appears that the oil of
vitriol makes a more minute and fubtile di-
vifion of nitre than what fimple water can
do ; that the fluid acid fait of the oil of vi¬
triol attracts one part of each real particle of
nitre, viz. the fixt and alcaline bails, while
this fame vitriolic acid feems to repell another
part of nitre, that is the acid and volatile
part.
332' ESSAYS AND OBSERVATIONS
part, which attrads, or is attraded by the
phlegm or watry part of the mixture, is ea¬
sily raifed up in vapour by heat, and turned
into a faline acid liquor.
It may be juftly queftioned, whether this
is an ultimate divifion of nitre, or a reparation
of it into its moft Ample principles or firft e-
lements. It is very hard to find an experi¬
ment that can give full fatisfadion in this
point $ for there are certain bounds fet to
art, as to the divifion of bodies : but if that
part of nitre, which unites with the acid
of vitriol into a neutral fait, is the fame with
nitre fixt by deflagrating with char-coal ; or
if it is no other than that fait which can be
extraded from the remains of the diftillation
of nitre with bole ; then we have fome rea-
fon to conclude, that this part of nitre is not
a Ample elementary matter : lince fixt nitre
1 can, by frequent folutions and fufions, be fo
changed, that little of it will remain, but a
mere earth.
Many of the folutions which happen in
chemiftry, are of the firft kind, that is, the
fol vents ad no otherways upon their proper
pbjeds than water does upon nitre or any o-
ther fait, by diflbiving the cohefion of the
larger
PHYSICAL and LITERARY.
333
-larger particles which compofe the body,
without reiolving the particles into their pri¬
mary elements.
When fpirit of nitre or aqua forth is
poured upon pieces of filver, the appearances
plainly point out that there is an attraction
betwixt the particles of the folvent and the
filver, and that there is likewife a repulfion
of the particles already diffolved from the
filver, to make way for the application of new
particles of the folvent to other parts of the
filver 5 for there is a remarkable motion and
agitation in the liquor, the furface of the fil¬
ver foon becomes rough and difcoloured, air
bubbles are formed upon it, which foon fly
off, and a conftant fucceffion of thefe arife,
break and diffufe themfelves : if a little of
this liquor is carefully taken off from the
top, even before half the filver is diffolved,
and dropt into a muria of fea fait ; it will
give evident marks that it contains a portion
of filver. When all the metal is diffolved,
the folution becomes clear and limpid, and
ail is at reft. Thefe things evidently fhew,
that fuch metallic particles as are freed from
their cohefion by the faline parts of the iren~
jiruum , recede with them from the filver,
^nc?
334 ESSAYS and OBSERVATIONS
and are fucceeded by other acid particles
to perform their part of the operation, until
all the parts of the folvent are equally char¬
ged with particles of filver.
The attractive force betweetf the faline
particles of the fpirit of nitre and the filver,
mu ft be fuperior to the power by which the
particles of filver attracft one another 3 for it
diffoives their cohefion, feparates them, and
keeps them fufpended in a fluid which has
only about one tenth part of the fpecific gra¬
vity of filver: yet thefe particles, thus fufpend¬
ed, differ in nothing, when freed from the
acid, but bulk from granulated filver or the
bits rubbed off plate by a fine file. That
this power of attraction between the particles
of fpirit of nitre and thofe of filver muft
be very great, will appear, if we confider,
ftrft, that it requires a very great heat to melt
filver ; but this melting is nothing elfe, than,
by the force of fire, to overcome the cohefi¬
on among the particles of filver, and bring
the mafs to a ftate of fluidity, fo that the par¬
ticles may eafily move and Aide one upon an¬
other while that degree of heat laftsj but
fpirit or nitre produces the fame or rather a
greater effeCt. In the next place, tho’ fpi-
PHYSICAL and LITERARY. 335
rit of nitre is of itfelf pretty volatile, yet,
when it has diffolved filver, the faline parts
adhere fo firmly to the metallic, that a very
ftrong degree of heat is required to feparate
them ; for, if a folution of filver is fet in a
heat that would make water boil, the light
and watry parts indeed fly off, but afterwards
the evaporation goes on {lowly, unlefs the
fire is confiderably increafed ; and, after fe-
veral hours, the matter has ftill the appear-
ance of a very moift fait, which is very cor-
rofive, and, in bulk and weight, greatly ex¬
ceeds the filver that was diffolved. When
the fand-heat can make no further change on
o
the mafs, put it into a crucible, and fet it in a
pretty brifk and clear fire: this expells the re¬
maining moift ure and fuperfluous acid 5 after
this the matter melts like wax, and, when
cold, is turned to a hard fubftance ; the
cauftic quality of which, the increafe of
weight above that of the filver, and its apt-
nefs to moiften, fhew, that, after all the heat
which the mafs has fuftained, there is ftill a
good quantity of the faline part of the fpirit
of nitre intimately incorporated with the fil¬
ver. Now, when a piece of this hard ftony
fubftance is put upon a piece of well kindled
char-coal.
336 ESSAYS and OBSERVATIONS
char-coal, and blown a little, it makes an ex-
plofion with a fparkling and flame, like a
piece of common falt-petre ; the faline mat¬
ter is confirmed or turned into flame or fmoke,
and the pure fllver is left on the coal. By
the way, this may be fome fort of proof,
that the volatile acid part of nitre is not more
a Ample elementary matter than is the fixt
part.
Notwithstanding what has been
fhewn, concerning the ftrong attraction be¬
tween the particles of fpirit of nitre and thofe
of fllver, and the difficulty of feparating
them by the force of fire ; yet, if a piece
of clean copper is put into a folution of fllver
in fpirit of nitre, the faline particles moflt
readily (hake off the fllver, and diffolve the
copper : which fhews that the particles of
copper have a ftronger attractive power, with
refpeCt to the fpirit of nitre, than the parti¬
cles of fllver have- ; which difference of at-,
traCtion will probably arife from the different
hulk, figure or denfity of the particles of the
two metals, the acid being the fame. The
fame thing may be faid of iron, zinc, chalk,
volatile alcaline fait and fixt fait, each of
which attraCl fpirit of nitre more ftrongly
PHYSICAL and LITERARY. 337
than filver does, and the laft more than the'
preceeding.
Here then we have a feries of bodies
from (ilver to fait of tartar, whole attractive
powers, with refpeCt to the fame faline li¬
quor, are continually increasing; but, whe¬
ther uniformly or in any certain proportion,
is not eafy to determine : there may be found
a body which attracts the acid of nitre more
than the firft, and Jefs than the fecond, and
fo thro’ other degrees ; which can only be
afcertained by a great variety of trials.
As the fait of tartar, or any ftrong
fixt alcaline fait, is the ftrongeft attraCter of
the nitrous acid, and throws down or Sepa¬
rates any other body that has been diffolved
in it ; fo it likeways attracts every other acid,
and disjoins it from whatever it has diffolved :
therefore we may confider that fait as a Stand-
dard whereby to compare the feveral attractive
powers of the different acid liquors. But it
is certain, from the experiments that have
been related, that, if three parcels of the fame
fixt alcaline fait, are joined to the three dif¬
ferent acids of nitre, fea fait, and vinegar, and
if oil of vitriol is poured upon each of thefe
faline mixtures or compound falts ; the vitrL
U u olio
33S ESSAYSand OBSERVATIONS
olic acid will attract, or be attracted more
ftrongly by, the alcaline fait than the other
acids, which will be driven from their places ;
and the acid of vitriol will be fo firmly united
to the fixt fait, that no other acid or known
body is capable to feparate them.
Again, If fpirit of nitre is poured upon a
compound faline liquor, or fait made of fpi¬
rit of fea-falt and fait of tartar, and upon an¬
other made of fpirit of vinegar and the fame
fait of tartar ; the fpirit of nitre, by its fuperi-
or attractive power, will join itielf to the al¬
caline fait, and drive away the other acids 5
hut is not able to refill the Hill greater force
of the vitriolic acid.
Lastly, If fpirit of fea-falt is poured up¬
on a compound of fpirit of vinegar, or any
other vegetable acid and a fixt alcaline fait -y
this will be more ftrongly attradted by the
acid of fea-falt, than by the vegetable acid
which will be expelled : but the fpirit of fea-
falt may likewife be diflodged by the acids of
vitriol or nitre.
In molt folutions, precipitations, and other
operations by which the texture of bodies are
much changed, there are fome appearances,
fuch as an expanfion and bubbling, the pro¬
duction
PHYSICAL and LITERARY. 339
duCtion of an elafiic fluid like air, and a com¬
motion fo great, as to produce fome remarkable
degree of heat, and in fome cafes fmoak and
flame : which appearances, I fay, plainly dis¬
cover, that the Small particles of bodies are
endowed with fome very aCtive powers, ca¬
pable to introduce certain motions tending to
union or disjunction, attraction or repulfion.
That many parts of matter are endowed
with an attractive power tending to union
and cohefion, may be deduced from the in¬
stances already mentioned : and many more
might be brought from occurrences in che¬
mistry to confirm the fame. That other
parts of matter are endowed with an elaftic
or repelling force, may be concluded from
the properties of air and light, demonstrated
by the greateft philofophers of the laSt and
prefent age. The curious experiments of
the ingenious Dr. Hales , in his Analyjis oj
the air , and the furprifing experiments on
electricity now fo much in vogue, may
Satisfy us, that particles of the fame nature
and qualities with thofe of air and light, may
be joined to particles of a grofler nature
and attractive quality, in various maSTes of
matter, to fome adhering more loofely, to o-
thers
1 4o ESSAYS and- OBSERVATIONS
thers more firmly connected. For fome
time they may lie concealed without mani-
nifeft motion or addon ; their repelling or
elaftic power being overcome or balanced by
the attractive force of the furrounding cor-
pufcles, till by certain concurring circum-
ftances, as external motion, heat, moiflure,
the addition of other matter, &c. the attra¬
ctive force is diminifhed, or the repelling in-
creafed : then they are roufed, as it were?
into adion, and difcover themfelves by great
and remarkable effeds, in changing the tex¬
ture of the maffes to which they were united.
Such changes we daily fee happen in fermen¬
tations, putrefactions, effervefcences, foluti-
ons, acceniions, explofions, &c.
Thefe principles of motion in matter, are
not the vain fictions of men merely fpecula-
tive in philofophy, but evidently deduced
from obfervations and experiments on a great
variety of bodies in, many different circum-
fcances ; and every one who reflects upon
the moil ordinary occurrences in the works
of nature and art, will be convinced of the
exhlence of fuch caufes, and find that they
gre io univerfal and unalterable, that they can
poly be referred to the firft caufe, that is, to
fhe will of the Supreme Being.
A R T.
PHYSICAL and LITERARY. 341
Art. XII.
Experiments and Objervations upon the Hartfell
Spaw, made at Moffat 1750 ; and an Ac¬
count of its Medicinal Virtues, fo far as they
have hitherto been dfcovered prom experience ;
by William Horserurgh, M. D .
^TT^HIS Spaw fprings from the Hartfell
JL mountain, about three miles north of
Moffat ; and is commonly called Willi amfon s
water , from Mr. John Willi amfon , who dis¬
covered it in 1748, and who has been at a
good deal of pains, and fome expence, to
make it acceffible, by mending the road,
clearing away the dirt about the fpring,
and fitting it with a fpout, that it may be
more conveniently taken up.
The water on which I made the following
experiments, had been taken up three or
four days from the fpring, and was contained
in bottles well corked and waxed ; it was ta¬
ken up on the 26th of Augufl , after a very
rainy feafon.
1. It was quite clear and pellucid.
2o It
342 ESSAYS and OBSERVATIONS
2. It had a fharp, aluminous, ftrong cha¬
lybeate, and ftyptic tafte.
3. It curdles with foap.
4. Its fpecific gravity to that of Annan ri-
ver water (which is efteemed the beft water
they have hereabout) is, as four ounces five
grains, to four ounces eleven grains.
5. By fhaking it in a vial, or mixing it
with tartifh wine and fugar, it gives no figns
of its containing a fpirit more than river-
water.
6. When boiled with an equal quantity of
new or fweet milk, it does not curdle the
milk.
7. With fyrup of violets, it gives a faint
green.
8. With powder of galls, it prefently be¬
came blue 5 and turned gradually darker,
till it became of a deep purple, and then of
an ink-colour : it does the like with an in-
fufion of tea, tho’ not in the fame degree as
with the galls.
9. When oleum vitriolic or fpiritus vitriolic
is dropt into it, no effervefcence, or change
of colour, is produced.
10. With oleum tart art per deliquium , it
made no effervefcence 5 but light green clouds
gathered^
PHYSICAL AND LITERARY. 343
•gathered, and were fufpended, in the mid¬
dle of the water 3 and a great number of
fmall air-bubbles, like particles of quick-fil-
ver, appeared adhering to the bottom of the
glafs, to its fides, and upon the furface of
the water 3 multitudes of the like air-bubbles
were intermixed with the green clouds : after
Handing about an hour, a great many of the
air-bubbles difappeared, and the clouds in the
middle of the water grew thicker, and of a
darker green, and afterwards precipitated.
1 1 . An aqueous folution of faccharum Ba¬
tumi ^ turned it a little whitiih, but not fa
much as it did the river- water 3 and much
lefs than it did the river-water, when there
was a very little fea fait diflfolved in it 3 in all
thefe three trials, a white powder precipita¬
ted*
12. On September iH, I poured a chopin or
Englijh quart of this water into a clean, white,
Hone-bowl 3 and covered it with a piece of
paper, to keep out the duH.
On the ad, there was precipitated a brown
powder, like brick-duH 3 and, on the furfacc
of the water, there were many finning
fpangles of a copper-like colour.
On
344 ESSAYS and OBSERVATIONS
On the 3d, there was more of the brown-
Eh powder at the bottom 3 all the parts of the
bow!, which were covered with the water,
were tinged yellowifh 3 a pellicle covered the
furface of the water, and all the fpangles
were gone.
On the 6th, the {harp aluminous tafte
was pretty ftrong, but the chalybeate tafte
much weaker 3 there feemed to be no more
of the brownifti powder at the bottom than
there was on the 3d 3 the yellow fubftance
that adhered to the bowl Was alfo thicker,
and had a fmooth oily look 3 the pellicle on
the top had now acquired the thicknefs of
writing paper 3 it was eafiiy taken up, as it
adhered to any thing put into it, and was of a
golden colour : I took up as much of the
water as filled a wine glafs 3 and, with pow¬
der of galls, it immediately ftruck a blue.
On the 13th, the fharp aluminous tafte
ftiil remained ftrong, but the chalybeate was
icarce to be diftinguiftied 3 the quantity of the
precipitate, and the pellicle on the top, were
much the fame 3 but the yellow fubftance,
adhering to the bowl, was rather more : into
a glafs of this water, I dropt fyrup of violets 3
it turned of a faint green : to another glafs
PHYSICAL and LITERARY. 345
of the fame, I put powder of galls ; it im¬
mediately (truck a blue tindlure, but not fo
deep as on the 6th.
On October 9th, it had a more aluminous
tafte, than the frefh Spaw water ; the chaly¬
beate tafte was fcarce to be diftinguifhed j
the precipitate, yellow fubftance adhering to '
the bowl, and the pellicle on the furface,
much the fame as on the 13th ult. 5 the wa¬
ter was as limpid as on the firft day} fyrup of
violets changed its colour to a deeper green
than before, and, with powder of galls, it
immediately gave a blue tincture.
13. I boiled a chopin of this Spaw water,
in a clean tin pan, till there remained of it
only one fourth part ; it turned of a yellow-
ifh colour and was muddy : when this was
cold, and the okry flakes precipitated, it had
a harfher and more aluminous tafte than the
frefti Spaw water, or than that which had
been fo long expofed to the air (12.). To a
glafs of this I put powder of galls ; it
changed very flowly, and, after it had flood
about eighteen hours, it exhibited a faint blue.
14. In a clean tin-pan, over the fire, I e-
vaporated a chopin of the fame Spaw water,
till there remained only about one ounce and
X x 2.
346 ESSAYS and OBSERVATIONS
a half; this I immediately poured into a China
tea-cup, and, when cold, filtrated it : the fil¬
trated liquor was clear and limpid, and had a
ftrong chalybeate tafte ; this was evaporated by
a fand-heat, in a wide- mouthed glafs ; there
was left a fait of a whitifh-brown colour,
which had an aluminous, and ftrong chaly-
be ate rough tafte. The whitifh-brown co¬
lour of the fait was owing, I believe, to its
having been a little fcorched at the bottom
of the glafs ; for, when I afterwards gently
exhaled the water before the fire, the fait
was of a pure white.
15. A little of this fait put into a glafs of
water, made the water of a yellowifh co¬
lour ; and, in a little time, it began to fepa-
rate into fmallyellowifh coloured flakes, which
growing gradually larger, and thicker, pre¬
cipitated ; after handing a night, the water
was quite clear, with a few detached, fmall
flakes, floating clofe to the Tides of the glafs ;
the water had the original tafte of the Spaw ,
but rather ft r on ger.
I poured off the clear water, half into
one glafs, and half into another : into the
firft poured off, which was the cleared, I
dropt fyrup of violets ; after handing a little,
it
PHYSICAL and LITERARY. 347
it gave a faint green tindure : to the other
half, I added powder of galls ; it flowly
changed to a violet colour, then to a purple,
and, after {landing all night, it was of a ve¬
ry dark blue, inclining to black : into the re¬
maining water, with the fediment, I dropt
fyrup of violets, and ftirred all about ; it
caufed a tindure of a deeper green than the
clear water : all thefe three mixtures, which
did not exceed an ounce and a half, I pour¬
ed into a chopin of common water ; and
the whole became of a deep violet colour.
16. This fait, after ol. tartari p. d. has
been dropt upon it, and then diffolved in a
little water, yields a deep green.
17. The fait of this Spaw , after it is
burnt on a hot iron, exhibites the like phe¬
nomena (15), and always lofes its aluminous
tafte.
18. This fait turned moift and bubbled on
a hot iron ; and, when calcined in a crucible,
it became of a purple colour, exadly like
that of the vitrioli Marti s calx rubra ; and
there was a manifeft attradion of feveral of
jts particles by the magnet.
19. Neither the fait nor earth of this
SpaWy make any effervefcence with fpiritus
vitrioli s
34s ESSAYS AND OBSERVATIONS
vitriolic oleum vitricli, or oleum tartaric p. d>
when by themfelves, or when diluted with
water ; nor does the fait emit any fumes with
oL vitrioli :
20. A glafs of this water, into which
ten gutts of oL tart, p . d . were dropt, and
another glafs of the fame water, turned, with
powder of galls, to a faint violet colour ; be¬
ing mixed together, produced exactly the co¬
lour of old red port- wine.
Experiments made on the fame Spaw Water ,
taken up Odober 12. 1750, after five
or fix Weeks of dry Weather .
21. The fharp aluminous tafte was much
weaker, and the chalybeate ftiptic tafte fcarce
to be diftinguifhed.
22. With fyrup of violets, even after
(landing all night, there was a little, and but
very little, tendency to green.
23. With oL vitriolic no effervefcence, or
change of colour.
24. W ith gL tart.p . d. no effervefcence 1
but the like clouds appeared as (10), tho5
in imaller quantity, and of a yellow colour.
With fcarce any green.
25. With
PHYSICAL and LITERARY. 349
• 25. With the Eolation of faccharum Ba¬
tumi, it gave a little milkinefs, but fcarce to
be diflinguifhed.
26. With powder of galls, it changed
very flowly 3 and, after Handing a night, it
exhibited but a faint violet colour, fomething
inclining to purple.
2 7. A chopin of it, evaporated in a clean
tin-pan, yielded a very white faline fubffance,
of a (harp, aluminous, chalybeate and Hip-
tic tafle.
28. A chopin of this Spaw water, taken up
from the fpring, after a long rainy feafon,
yielded of fait, nine grains 5 and of earth,
fomething more than one grain : the like
quantity taken up after three weeks of dry
weather, gave of fait, but feven grains 3 and
of earth, about half a grain : the like
quantity taken up, after between five and fix
weeks of dry weather, afforded of fait, on¬
ly five grains and a half 3 and of earth, a-
bout a quarter of a grain.
29. 1 here is another fpring, about forty
foot Irom this, which feems to be of the
fame kind 5 for it has the like tafie 3 and,
with fyrup of violets, powder of galls, oh
vitriolic oh tartan , p. d. and the folution
of
35o ESSAYS and OBSERVATIONS
Jaccharum Saturni, it exhibit es the like phe¬
nomena.
From the preceeding Experiments we may oh~
ferve ,
l That this Spaw contains a principle
of iron, which is volatile ; for its chalybeate
quality is much weakened by boiling (13),
or even by being expofed for fome time to
the air (12).
2. It contains an iron-principle, which
is fixed 5 for its chalybeate quality is not in-
tirely deflroyed, by being expofed to the air
(12), nor by boiling (13)3 nor by evapora¬
tion to a drynefs (14, 15), nor by burning
the refiduum (17) ; and, when its fait is cal¬
cined a fufficient time, it is attracted by the
magnet (18).
3. It fecms, by turning green with fyrup
of violets, to contain an alcaline principle,
which is likeways fixed ; for neither by be¬
ing expofed to the air, nor by evaporation
to a drynefs, nor by burning the rejiduum ,
does it lofe this quality.
As neither the water nor its fait or earth,
make the leaft vifible effervefcence with fpi-
ritus, or oh vitrioliy either bv the mfelves, or
when
PHYSICAL and LITERARY. 351
When they are diluted with water ; fo, it may
be faid, that it contains no alcali, and that
its turning green with fyrup of violets, is
of itfelf no proof; becaufe common water
does, with fyrup of violets, change to a faint
green colour, after it has flood fometime:
but this I imagine rather to be a proof, that
there is in common water an alcaline princi¬
ple, viz. abforbent earth ; for rain-water,
or fnow-water, have not the leaf! tendency
to green, with the faid fyrup.
4. It feems to contain a very little fea fait
(lefs than common water) by its precipitating
the folution of faccharum Saturni (11).
5. It feems to contain lbme portion of il¬
ium.
<*. From the tafle of the Spaw water, as it
comes from the fpring, which is remarkably
aluminous.
£. From its tafle becoming more alumi¬
nous, when part of the water is exhaled,
by being expofed to the air, for between five
and fix weeks (12).
y. From its tafle after three fourths of the
water was evaporated, which was more harfh
and aluminous, than that of the frefh Spaw,
or
352 ESSAYS AND OBSERVATIONS
or than that which had been fo long expofed
to the air (13).
From the aluminous tafte of the fait
(14, 27).
£. From its fait fwelling and riling into a
blifter on the hot iron (18).
£. From this fait lofing its aluminous tafte
when calcined a fufficient time ( 17), which
alfo happens to alum, when treated in a like
manner.
The nitrum murale, it is true, alfo fwells
and rifes in blifters on the hot iron 5 like ways
borax, and the purging fait of Scarborough-
water : but the nitrum murale differs from
this fait in tafte, and, when calcined, falls
down into a loofe powder, like lime ; which
this fait did not do, tho’ calcined for a confi-
derable time, in a ftrong fire.
Borax likeways differs in tafte from this fait,
and vitrifies in a moderate heat, in a few mi¬
nutes • which this fait did not, after being
calcined in a ftrong heat for a confiderable
time. T his fait has not the bitter penetra¬
ting tafte of the purging Scarborough- fal t,
neither its purging quality.
I don’t however pretend that all thofe
marks amount to a demonftrative proof that
there
PHYSICAL and LITERARY. 353
there is alum in this water, but only to a
great probability : for, to be fure of it, we
muft fee the alum chryitallifed, which is not
eafily done * ; and requires, for that procefs,
a greater quantity of fait than I had.
It may be objected, that, when equal
quantities of this water and new milk were
boiled together, the milk did not curdle(6.) ;
therefore there can be no alum in it. This
objection is fpecious ; its validity, however,
like that of many other things which have ve¬
ry plauhble appearances, can only be determi¬
ned from experiment : wherefore I diifolved
in water a greater proportion of alum> than
there is, or feems to be, in this Spaw ; and,
when equal quantities of this folution, and
frefh milk, were boiled together, the milk
did not curdle.
6. This water contains very little earth,
it gives not the lead: fign of it, when cL tart .
p . d. is dropt into it; but the little it contains,
feems to be of the white calcarious kind :
and tho’ okry-earth is commonly allowed to
be a confiituent principle in chalybeate wa-
Y y ters,
* Vid. Shaw’s Inquiry into Scarborough* water, part i. § 4-
art. 43.
354 ESSAYS and OBSERVATIONS
ters, yet I am of opinion, that no fuch thing
exifts in them in a found, natural ftate ; and
that it is never to be found, till the acid,
or whatever it is, that diffolves the iron-
principle, leaves the water, or, at leaft, its u-
nion with the iron-principle, then it ap-
pears in the form of an okry fubftance ; but,
while the diffolvent of the chalybeate princi¬
ple remains united to it, that is, as long as the
water continues in a found ftate, okry-earth
is never to be found in it. The earth, there-^
fore, of this kind, which is left in the filter
after evaporation and filtration, is owing to
its diffolvent principle being loft in that pro-
cefs. And I have reafon to believe, from ex¬
periments which I have made, that, by re¬
peated folutions, evaporations, and fiitrations,
the pureft and mod genuine cryftals of vi~
triolum Martis may be all reduced to an okry,
or bolar earth ; efpecially if the folutions be
made in common water.
7< The quantity of mineral principles in
this water varies ; and is lefs after a dry fea-
fon, than a wet one (28); an unufual circum-
fiance, which probably proceeds from this
caufe, that the water in a wet feafon, rifes
higher in the veins, which contain the mine¬
ral
PHYSICAL and LITERARY, 355
ral principles, and confequently diffolves and
carries a greater quantity of thefe principles
along with it. Whence it is likewife evi¬
dent, that experiments made on this water at
different times, will not always exactly cor-
refpond, but will vary more or lefs, in pro¬
portion to the mineral contents of the water.
8. The tenth experiment feems to be an
indication, that this water contains a vitriolum
Martis nativum ; no other mineral water, that
I know of, turns green, with oL tart, p. d. :
but, when this oil is dropt into a folution of
vitriolum Martis , it becomes green. And
tho’ there is no vihble effervefcence in this
experiment (To,), yet the many air-bubbles
generated feems to be the effedt of the alka¬
li’s uniting itfelf to the acid, which kept the
chalybeate principle diffolved, and which
chalybeate principle, being now by the oLtart ,
difengaged from its diffolvent, appears in the
form of green or yellow clouds 5 and at kift is
found, at the bottom of the glafs, under the
form of a fubtile okry, or bolar earth.
It may perhaps be faid, that iince there is
probably alum in this water, the air-bubbles
are generated by the alkali’s uniting itfelf to
the acid of the alum. To deftroy this lup-
pofition2
356 ESSAYS and OBSERVATIONS
pofition, I diffolved alum in water, and that
in a greater proportion, than it can be in this
Spaw , and then dropt into it ol. tart.p. d. ; there
enfued no effervefcence, or fenfible change
upon the water ; but a few air-bubbles ga¬
thered at the bottom of the glafs ; nothing,
however, in comparifon of what appeared
when the ol. tartar . p . d . was dropt into the
Spaw ; and no more than what formed upon
dropping oL tart, p. d. into a giafs of pure
river-water.
9. As chalybeate waters, in feveral parti¬
culars, refemble a folution of vitriolum Martis
in water, hence many have been induced to
think, that thofe waters contained a vitriolum
Martis fuch as is prepared by art : but fome
of the late ft, and moil learned authors, as
Hoffman , Boerhaave , &c. are of a contrary o-
pinion, and for a very good reafon, becaufe no
vitriolum Martis could ever be found, upon
evaporation of chalybeate waters : the expe¬
riments however made on this Spaw, feem to
prove that it contains a fixed vitriol of iron ;
tor it not only turns green, upon the addition
qi ol. tart. ( 10.) , but like ways, upon eva¬
poration, there is a fait left, which has all the
properties of vitriolum Martis .
I
PHYSICAL and LITERARY.
357
■ I diffolved, in a chopin of fountain water,
vitriol. Mart . gr. xv. and in every refpedt
treated it as I had done the Hartfell Spaw-
water, viz . it was evaporated over the fire,
till there remained about two ounces ; this
was filtrated, and exhaled, in a wide glafs,
before the fire : there was left in the glafs gr.
xi fs of a light-yellowifh coloured fait, and in
the filter a dark-brown earth. With this
fait, I repeated all the experiments I had
made with the fait of th t Hartfell Spaw $ and
I had the pleafure to fee, that they corre-
fponded in every thing, without any material
difference ; only the fait left upon evaporation
of vitnolum Martis , did not rife in a blifter
on the hot iron, and, when diffolved in water,
gave, with powder of galls, a redifh tindture
inclining to purple : whereas the fait of the
Hartfell Spaw , being diffolved in water, with
galls, flruck a blue. The reafon of which
I take to be, that there is a greater propor¬
tion of acid, in the compofition of the fait of
the Hartfell Spaw , than there is in the vitrio -
him Martis 5 for, if you add an alkali, as oh
tartaric to the blue tindfure, produced by
the fait of Hartfell Spaw , it changes to a red¬
ifh 5 and if an acid, as oLvittioli , is added
to
S58 ESSAYS and OBSERVATIONS
to the vitriolum Mart is y (e.g. if to a folution
of two, three, or four grains of vitriolum Mar-
tisy in eight ounces of water, be dropt one
gutt. of ol. vitrioli) this, with powder of galls*
tho* indeed it changes but flowly, will give
a blue, not a redifh tinfture y and again, if
the acid is weakened, by dropping into this
blue tindlure ol. tartaric the blue will change
to a redifh* And this conjecture feems to be
confirmed by the following experiment, viz.
if vitriol. Mart . be burnt on a hot iron, till it
becomes quite dry, and of a yellowifh brown,
and diffolved in water, it gives much the
fame redifh purple with galls, as before it
was burnt ; if this burnt fal Martis be pow¬
dered, and the dry powder wrapt up in a An¬
gle paper, and left in a room without a fire
for three or four weeks, it will become moift,
and, when diiTolved in water, ftrikes with
galls no more the former colour, but a blue $
which, I prefume, is owing to the act dam va-
gum which it has imbibed.
Seeing therefore the fait of Hartfell Spaw
has all the properties of vitriolum MartiSy I
cannot fee, why it may not be allowed, that
this Spaw contains a native, fixed vitriol of i-
ron ; and it is the only water (I know of)
which
PHYSICAL and LITERARY. 359
which has been difcovered to contain fuch a
fait.
In the PhilofophicalTranfadtions, N° 245.
mention is made of two mineral waters*
which yielded a real, fixed vitriol of iron, one
near Eglingham in Northumberland , the other
near Haigh in Lancafhire ; but thefe waters
were found by Dr. Cay, who made particu¬
lar inquiry into the matter, not to be mine¬
ral fprings, but drifts made for the draining
of coal-pits 5 and that the vitriol found in
thefe waters, was owing to their running o-
ver marcafite beds which had been expofed
for fome time to the air. I was fufpicious
that fomething of this kind had communica¬
ted the vitriol to the Hartfell Spaw 5 but Mr,
Willi amfon , who difcovered the fpring, allured
me, that the water, on which I made the pre¬
ceding experiments, had run over nothing at
all, after its exit from the fpring, but was ta¬
ken up by himfelf immediately, as it ilfued
out of the rock. Dr. James Hunter, Phy-
fician in Moffat , afterwards fent me fome
of the fame water, which he received into
bottles, by applying their mouth to the ori¬
fice of the vein, in the rock from which it if-
fued 5 and from it I obtained cryftals of vitri-
olum
I
360 ESSAYS and OBSERVATIONS
olum Marti s, which were of a paler green
than the artificial.
In Auguji 1752, this Spaw , with fyrup of
violets, ftruck no green tindure.
With oL tart. p. d. it immediately turned
green, and clouds of a deeper green and more
in quantity than in Auguji 1750, were form¬
ed, and that much fooner than in the prece¬
ding experiments.
With powder of galls it fcarce changed
its colour ; and, even after ftanding fome
time, it exhibited but a faint blue. I was at
a lofs for the reafon of its giving fo faint a
blue with galls 5 when, at the fame time, I
knew, by its immediately turning green with
the oL tart., together with the quantity of
the clouds that prefently formed, and the
deepnefs of their green, that it was very
ftrong of the chalybeate principle : I there¬
fore fet the mixture before the fire, to fee
what change a little heat would produce;
and, when I obferved that a fmall heat had
no elTed, I gradually increafed the heat, till
bubbles appeared on the furface of the water ;
but this occafioned no change on the colour
of the water, the faint blue remaining much
the fame. I then conjedured, from the wa¬
ter
PHYSICAL and LITERARY. 36i
ter not turning green with fyrup of violets, as
in the former experiments, that there was a
greater quantity of acid than ufual united to
the chalybeate principle : and, to difcover
whether my fufpicion was right, I dropt into
the fame glafs, containing the water and pow¬
der of galls, one or two gutts ( I don’t re¬
member which) of ol. tart . ; and, having
mixed it by ftirring, it immediately produced
very deep blue.
From this experiment, I think it appears,
that a water may be very (Long of the cha¬
lybeate principle, and yet difcover very little
of it by the common experiment with galls \
fo that it may be proper always to try it with
the ol . tart, alfo : for the (Length of the iron-
principle is, as the colour and quantity of the
clouds formed by this oil ; that is, if the
clouds are of a light yellowilh colour and
fmall in quantity, the chalybeate principle is
weaker ; if they are of dark brown and more
in quantity, it is (Longer ; if they are of a
green colour, the deeper the green and more
in quantity, the (Longer is the chalybeate
principle $ which I have found to correfpond
with truth, by repeated experiments, not on¬
ly on this Spaw, but on folutions of vitriohim
Z 3 Marfa
n6 2 ESSAYS and OBSERVATIONS
Mart is of different ftrengths, in common wa¬
ter : but, how far this will hold in chaly¬
beate waters that are volatile, I have had no
opportunity to try.
I took a chopin bottle of this water, three
months after , it had been carried fifty fix
miles, and poured one half of it into another
clean chopin bottle, and then corked them both
very tight j the one bottle I fhook frequent¬
ly and ftrongly for two days ; the third day, I
tried both, with powder of galls and ol. tart .
j p.d. ; with the galls, both gave a very deep
blue ; but the water which had been fhaken,
with the ol. tart . rather yielded a fainter
green, than that which had not: I let both
bottles Rand corked up as before for ten or
twelve days longer, without fhaking \ then
tried them again with the galls and ol. tart. ;
they both ftruck much the fame deep blue,
tho’ not fo deep as at firft ; and, with ol. tart .
the water which had not been ihaken, gave a
green, tho5 fainter than at fir ft 3 the other
icarce offered any green ; the clouds formed
in it were fewer, and of a lighter yellow,
than thole of the other. From which it
feems, that fhaking fomewhat weakens the
chalybeate
PHYSICAL and LITERARY. 363
chalybeate principle of this water, tho’ not
much nor fuddenly.
This water feems to belong to the clafs of
the aqua Marti at a ; for it efferve'ces not
with acids, like the acidula and thenna ; nei¬
ther is its volatile iron-principle fo volatile as
theirs : hence in general, it may be faid to be
aperient and (Lengthening, both when ufed
internally and externally : whence it muft be
of ufe in difeafes where the folids are relaxed
and the blood too watery and weak. But,
altho’, when the principles of a mineral wa¬
ter are known, we may, from analogy, de¬
duce its virtues in particular difeafes ; yet, as
this method is not fo certain, no reafoning
being equal to experience, I (hall confine my-
felf to the laft alone ; tho* it is to be pre¬
fumed, that there have not been yet fuffici-
ent opportunities of difcovering all the vir¬
tues of a water fo lately found out. Howe¬
ver, it has been obferved to be of great ufe in
curing itchy, hot, tettarous eruptions, old
obflinate ulcers and fores, internally ufed,
and externally applied : it has likeways been
of great fervice in diforders of the flomach
and bowels ; in the bloody flux ; bloody u-
rine 5 (pitting of blood; immoderate flux
of
364 ESSAYS and OBSERVATIONS
of the menfes j obEruaion of the menfes$
the floor albus ; gleet; rheumatic pains;
in the firftftageof confumptions, and even
when they have been further advanced ; in
preventing mifcarriages 3 and in reftoring
health, when the conflitution has been im¬
paired by long illnefs : all which will ap¬
pear from the following hiflories, moft of
which were wrote down from the patients
Own mouths, and attefted by the phyfician
or furgeon who attended them*.
Before
* There were given in to the Society, with this paper, twen¬
ty two well attefted hiftories of patients cured of the above
mentioned difeafes, by meano of the Hartfell Spanv \ which it
was thought proper to omit, fince they would have (welled
this article to a bulk too great for a work of this kind. But
as the good effects of this water in confumptions of the lungs
are fomewhat extraordinary, and may, perhaps, be doubted
of by thofe, who have imbibed early prejudices againft all
chalybeates and aftringents, in fuch cafes; it may not be amifs
to give a place, here, to the two following hiftories.
1 . Mrs Gkndinning, wife to. Mr. Robert Glendinning , fchool-
mafter in Moffat, aged 51, was, on the 20th of December
5750, attacked with pains in her right fide ; a conftant (harp
pricking pain under the middle of the breaft-bone ; a hard,
tickling, dry cough ; third:, difficulty of breathing, and
frequent gripes in her guts : all which fymptoms increafed,
fill the fifft of January 1 75 1, when {he began to fpit, with
difficulty, a little thick grofs matter. In the beginning of
ftbruar y, the fpittingwas fp extremely foetid and ill-tailed.
PHYSICAL and LITERARY. 365
Before one enters upon a courfe of the
water, it will be proper to cleanfe the prime e
vice, by an emetic and a gentle- purge or two ;
unlefs forbid by fome particular circumftances
of
that it made her often vomit : fhe frequently wafhed her
mouth with fait and water ; but thill felt a tafte and fmell
which the thought refembled that of ftinking flefh : the now
became very weak and emaciated ; had he£tic fits and night-
fweats : which fymptoms continued increafing till the mid¬
dle of April ; about which time (having tried no medicines
before) fhe began to drink the Hartfell Spa w, to the quantity
of half an Englijh pint every morning. She had fcarcely
ufed it a week, when her breathing became much eafier :
after a fortnight, the fpitting loft the foetid fmell and ill-
tafte ; and, in three weeks, fhe was perfectly free of the
pain of her breaft, cough, fpitting, difficulty of breathing,
he&ic fits and morning-fweats : and has continued ever
fmee in good health.
2. Mrs. Haiti day in Barntyvipan , aged 28, of a plethoric
habit, complained, in the beginning of September 1750, of
a pain under the upper part of her breaft-bone, which fre¬
quently darted to the point of her right fhoulder ; a pain
in her head and neck ; her breathing was not quite free, and
fhe could not lie upon her right-fide. About the middle of
October , fhe began to fpit florid blood, which continued
three wreeks, at the rate of a fpoon-ful every day ; then
flopped a week, and returned again. In this manner it
went on about four months : after which, beginning to fear
the confequence might be fatal, as many of her neareft re¬
lations had been carried off by confumptions of the lungs $
fhe applied to Mr. Johnflon furgeon- apothecary in Moffat?
>vho, finding the fpitting of blood increafing, and her pulfe
pretty
366 ESSAYS and OBSERVATIONS
of the patient : or, if the patient’s body has
been long codive, and the excrements harden¬
ed^ emollient glyfters may be ufecL Such
as
pretty full and frequent, ordered her to be blooded, to
take the decodlum tamarindorum of the Edinburgh Difpenfa-
tory, and to fwallow four of the following pills thrice a-day.
R Extraft. cort . Peruvian, drach . ii. balfam. Peruvian. Jcrup. h
pulv. cort. Peruvian, q. f. ut f. mafia, ex cnjus fingul. drachm .
for merit ur pil. xii. The blooding and decoCtion were repeat”
edas often as they feemed neceffary; and the pills were con¬
tinued ten weeks without fuccefs: for foon, after fhe left off
ufing them, fhe began to cough up purulent matter with
blood. Whenever the fpitting dimimfhed, her breathing be¬
came very difficult ; and the pain of her breaft increafed,
with a particular forenefs ail along the breaft-bone when fhe
coughed.
She drank goat’s and ewe’s whey, from the beginning of
June , to the end of Auguft , without any fenfibie benefit ;
for fhe continued ftill to fpit blood and matter : foon after
this, fhe was attacked with fudden flufhes of heat and morn¬
ing fweats, which increafed till the middle of January 1752,
when fhe was become feebler, much emaciated, and often
faintifn. At this time, fhe was advifed to drink the Hartfell
Spavo in fmall quantity ; but, finding it fit eafy on her (to¬
rn ach, fhe drunk an Englifi pint of it daily. During the firft
week after drinking the water, (he expectorated dark, blueifh,
putrid fluff, without blood ; and found her breaft much
eafier than it had been any time from the beginning of her
iljnefs. Soon after, lhe began to breathe freely ; and, after
having drank the water fix weeks, was perfectly recovered :
fince which time, fhe walked, or rather run, three Scotch
miles in an hour, without being either hurt, or much fatiguecf
by it.
PHYSICAL and LITERARY. 367
as are plethoric, or have their veffeis full,
fliould let a little blood.
This water may be drunk at all times of
the year : tho’ I prefer the fummer or warm
months ; becaufe perfpiration is then freeft,
and the operation of the water, as an alte¬
rative, is aftifted by the warmth of the wea¬
ther : befides, this feafon is more convenient
for the ufe of exercife, and the patients are
lefs apt to catch cold. The propereft time of
the day for drinking it, is, when the ftomach
is mo ft empty, as in the morning, fallings
before dinner, and fometimes in the evening.
Some patients have a cuftom of drinking it
with their victuals : but I don't approve of
this 3 as it may retard, or, in fome meafure3
hurt digeftion.
The quantity to be drunk is to be deter¬
mined by the age, ftrength, and other dr-
cumftances of the patient: they ought to
begin with a fmall dofe at firft, and increafe it
gradually: fuch as are very weak and much
extenuated, fhould begin with a gill or lefs ;
this quantity they may take twice a-day ;
and, by degrees, increafe it, in proportion as
they recover their ftrength, till they come to
arink an Englijh pint a-day, a pint and an
half.
568 ESSAYS and OBSERVATIONS
>
half, or two pints, which is about a Scotch cho-
pin, and is the larged quantity ufually drunk
of this water in twenty four hours, If the wa¬
ter fhould be uneafy on the domach, the pa¬
tient may mix with it an equal quantity, or
lefs, of new milk, or fuch a proportion of it
as may be found moft convenient: it may
alfo be proper to warm the water.
As few of the patients, whofe cafes I have
collected, obferved any rule in their diet or
exercife, and neverthelefs met with a cure
this (hows that there is no great dridtnefs re¬
quired in thefe matters : and, indeed, fuch
as have any tolerable degree of health and
ftrength, need not much recede from their or¬
dinary way of living; tho5 temperance in eat¬
ing, a moderate ufe of wine, and gentle exer¬
cife, is what all infirm people fhould conform
themfelves to : but, fuch as are very weak,
and much emaciated, or that labour under
dangerous difeafes of the lungs, or abdomi¬
nal vifcera , muft obferve a very dried regi¬
men; their diet fhould confift of what is
lighted and eafied of digedion, fuch as n ew
milk, broths, panadoes, thin jellies, frefh
eggs, chicken, veal, fowls, &c. ; and a
little wine may be allowed, when not prohi¬
bited
Irf O-
PHYSICAL and LITERARY. 369
bited by the circumftances of the patient ;
moderate exercife may be proper for feme,
and reft for others; they mu ft avoid the night
air, fitting on the grafs, and every thing that
difcompofes the mind.
Upon the firft ufe of this water, feme
complain that it makes them lick, others
that it makes their head giddy ; but thefe
inconveniences almoft always proceed from
their having taken too large a quantity : the
dofe is therefore to be diminifhed; and if,
in a fmaller quantity, it fliould be uneafy on
the ftomach, chewing cinnamon, or cara¬
way feeds, or comfits made of them, are
frequently ufeful; or any other aromatic, moft
agreeable to the patient. It fometimes occa-
fions gripes, when the inteftines are weak, on
account of its coldnefs ; it ought therefore
to be warmed ; the beft way of doing it, is,
to put as much as the patient intends to drink
at one time, into a vial ; cork the vial, and
fet it before the fire, or put it into warm wa¬
ter, till it acquires a fufficient degree of heat.
On its firft ufe, it fometimes purges fuch as
are troubled with a diarrhoea ; but that is
to be reftrained by a gentle emetic, or by
giving fame gutts of the tinSi. cpii in every
A a a dofe
37o ESSAYS an£> OBSERVATIONS
dofe of the water, or rather fome little time
before it; or three or four grains of the piL
Matthcei may be given at bed time, and as
much, if requifite, in the morning: it will
be convenient likeways to warm the water,,
But it oftener occafions ceftivenefs; for which
it will be proper, now and then, to give a
little fal. Glaub . polychr . manna , or cream of
tartar ; or, which perhaps is preferable to a-
ny of them, the purging fait of Scarborough -
water. If, upon catching cold, any fe¬
ver i ill fits fhould arife, the ufe of the water
muft be fufpended till thefe fymptoms are
gone. When the water does not pafs eafily,
it will be proper to loofen the belly, or give
diuretics ; and fuch whofe ftrength will per¬
mit, and whofe veffels are full of blood and
juices, fhould let blood.
There is no determining precifely how
long it fhould be drunk ; the advantage the
patient reaps from it muft decide that :
fome have uied it only twelve days, others
three weeks, others four, others fix, fome
two months, and others many months ; and
yet they have all been fo happy as to meet
with a cure : fo that, in general, as long as
there is any profpedt of its working a cure,
its
PHYSICAL and LITERARY. 37E
• its ufe fhould be perfxfted in ; and, tho' the
patient may think himfelf well, I am of o-
pinion he (hould not immediately difcontinue
its ufe, but gradually diminifh the quantity.,
and leave off by degrees. Some recommend
purging, and other medicines, after the courfe
is finifhed ; but, if the patient has been cured,
all medicines are ufelefs, and rather hurtful ;
if the cure has been impeded, then fuch
helps may be called in as the cafe requires.
As to the external ufe of this water : the
pradice has been, to waih with it, when
warmed, itchy, hot, tettarous eruptions,
and old obftinate ulcers, two or three times
a-day, and, in fome cafes, during the wdiole
day ; to keep linnen cloaths wetted in the
fame water, applied to the parts affeded;
which method has been very fuccefsful? but,
it muff be remarked, that the water was
always ufed internally alfo, in the fame cafes.
It feems proper to obferve, that, as this wa¬
ter, put in bottles, well corked and waxed,
may be carried to any diflance, and will keep
good a long time; longer than either the Pyr-
mont water or Liege Spaw : people living in
any part or Great Britain , or even beyond
leas, may reap almofl: the fame benefit from
it, as thofe who r elide in its neighbourhood.
A r Tf
372 ESSAYS and OBSERVATIONS
Art. XIII.
Of the various Strength of different Lime-
waters , by Robert Whytt, M, D,
F. R. Sa Fellow cf the Royal College of Phy -
fcians , Profeffor. of Medicine in the U-
niverfty of Edinburgh.
THE Reverend and ingenious Dr. Ste¬
phen Hales , having informed me, in
a letter dated May 1751, that he had found
the ftrength of lime-water much increafed,
by pouring it a fecond time on quick-lime,
frefh from the fire ; I thought it might be
worth while to make a few experiments,
in order to determine, with fome degree of
certainty, the different ftrength of different
lime-waters : from thefe experiments it ap¬
peared, that lime-water acquired a confider-
able addition of ftrength by being poured on
quick-lime newly taken from the fire ; and
that the firft water got off quick-lime, was
fenfibly ftronger than the fourth and fuc-
ceeding ones *a
On
* EBay qn the virtues of lime-water, Sx . p. 38 39,
PHYSICAL and LITERARY. 373
. On the other hand, my worthy friend
and Collegue Dr. Alflon, having obferved,
feveral years fince, that quick-lime continued
to communicate its virtues to water much
longer, than any one, before, had imagined 3
tells us, that he found afterwards, by expe¬
riments, that half a dram of ftone quick¬
lime yielded forty ounces of lime-water 3 and
that, after a pound of the fame quick-lime
had afforded five hundred pounds of lime-
water, the water procured from it was as
ftrong of the lime as ever *. Hence he i- *
magines, that as water can only be impreg¬
nated, to a certain degree, by quick-lime, fo
this will happen equally, whether the quick¬
lime be frefh from the fire, or has had five
hundred times its weight of water poured on
it before 3 provided the water be allowed time
enough to extradl the virtues of the lime *j~.
And further affirms, that the ftrength of lime-
water cannot be increafed by flaking new-
made lime in it, becaufe the water can take
up no more of the lime than it had before j.
As
* Philofoph. Tranfaft. vol. 47. p. 266, and D:fTertation
on quick-lime, &c. p. 4, 5, & 6. where the fame thing is
affirmed of oifterihell-lime.
■\ Diiiert. on quick-lime, p. 11. & 53.
x Id. p. IJ,
374
ESSAYS and OBSERVATIONS
As thefe experiments and conclufions ap¬
peared inconfiftent with what I had advan¬
ced, the DoBor has endeavoured further to
weaken the credit of my experiments, by fome
arguments drawn, chiefly, from the imperfe¬
ction of the hydroflatical balance, and from
the nature of quick-lime and its water. In
order therefore to know whether I might not
have been miftaken in what I had faid, con¬
cerning the ftrength of different lime-waters,
I thought it neceffary to make fome new ex¬
periments ; an account of which I beg leave
to lay before the fociety.
I. ( a ) Having got from my ingenious
friend Mr. James Cray , a cylindrical copper-
veffei ending in a narrow neck, which con¬
tained exadly ioo cubical inches; I filled
it with the fountain water of this city, and,
by means or a very nice balance, found it
weighed 25320 Troy grains # befides the
weight or tne veflel itielf, which amounted to
*3°55 grains; (£) I
According to Mr. Grays experiments, the water which
this veffei contains, qnly weighs 25318 grains, two
grains lefs than we have made it. See above, p. 20 1.
This difference may have arifen from our having pur* few
pore drops of water into the veffei than Mr. Gray did. But
al|hQ*
PHYSICAL and LITERARY. 37$
• (b) I poured upon 90 grains of calcined oi-
fterfhells, newly taken from the fire, and re¬
duced to a powder, 96 ounces, or five hun¬
dred and twelve times their weight of boil¬
ing water. After 92 hours, during which
time the infufion was frequently ftirred and
fhaked, I decanted off the clear water, and
filtered it thro' a piece of very thick iinnen-
cloth doubled 5 by which means it was ren¬
dered free of any crufts, and equally pellu¬
cid with fountain water. With this lime-
water I filled the above vejfel , and found its
weight to be 25356 grains*.
(c) Monday, at feven in the evening, I
poured upon a pound of calcined oifterfhells,
frefh from the fire, ten times their weight
of water ; next morning at ten, I decanted
off the clear lime-water; and having filtered
it
altho, in weighing fluids with this veflel, one might err fix
times more than this, yet it would not affeft the point we
have in view, which is not to determine with the greatefl
accuracy the different fpecific gravities of different lime-
waters, but only to fnew that they are different.
* The oiflerfhells made ufe of in this, and the following
experiments, were got from among the rubbifh on the fouth
fide of the Caftle of Edinburgh, and were quite free of any
fea fait.
376 ESSAYS and OBSERVATIONS .
it as above, filled the vejjel with it 5 it weigh¬
ed 25297 grains.
(d) Tuesday at mid-day, I poured feven
pounds of the fingle lime-water, ( c ) upon
one pound of calcined oifterfnells, newly ta¬
ken from the fire, ftirring them well for
fome time after $ at three quarters paft fix
in the evening, I decanted off, and filtered
as above, the clear lime water ; and, having
filled the roeJJel with it, found its weight to
be 25457 grains.
HENce it appears, that 100 cubical inches
of the lime-water (b) exceeds, in weight,
that quantity of fountain water by 36 grains :
( c ) exceeds it by 77 grains, and ( d ) by 137
grains.
The fpecific gravity therefore of the weak
lime-water ( b ) is to that of fountain-water
nearly, as 704 to 703. The fpecific gravity
of the fingle lime-water ( c ) is to that of com¬
mon water, nearly as 329 to 3285 and the
double lime-water ( d ) is in fpecific gravity
to water nearly, as 186 to 185.
It is obfervable that the fpecific gravities
of the fingle and double lime-waters (c) and
(d) y are confiderably lefs than the fpecific gra¬
vities of the tingle and double lime-waters ( a )
and
PHYSICAL and LITERARY. 377
A. and B. mentioned p> 39. and 40. of my
Effay on the virtues of lime-water, &c. But, if
it be coniidered, that, in making the latter, a
much lefs proportion of water was added to
the quick-lime, than in making the former %
it will appear that this difference of their fpe-
cific gravities, does not infer any thing againfi
the accuracy of the hydroftatic balance ; but
clearly fhews, that the ftrength of lime-
water varies according to the quantity of wa*9
ter poured on the quick-lime.
It may be worth while to obferve, that the
fpecific gravities of the lime-waters, [b\ (c)
and [d] did not differ more than their taftes*
The firft was weakeff and leaft difagreeable 3
the fecond was flronger ; and the third {fill
ftronger and fomewhat pungent. Further,
while the double lime-water [d) gave, in a few
minutes, a copper-colour to {liver; the weak
lime-water (b) produced no fenfible change
upon it.
II. Having, formerly, found that lime-
water and claret wine, mixed together, in a
certain proportion, acquired a colour like
that of gun-powder^: I thought, that, by
mixing claret with different lime-waters, one
B b b might
* EiTay cn the virtues of lime-water, p. 47*
37S ESSAYS AND OBSERVATIONS
might judge whether they were all equally
ftrong of the lime or not. The refult of
the experiments was, that one tea-fpoonful of
claret required four tea-fpoonfuls of the lime-
water (b) ; two and about one third of (c) y
and one and a half of (*/), to give it the full
gun-powder colour. Thefe experiments,
tho? not fo accurate as thofe made with the
balance, yet clearly demonftrate a remark¬
able difference of ftrength betwixt the above
lime-waters.
III. Twenty grains of fait of tartar be¬
ing mixed with eight ounces and two drams
of the weak lime-water (b), after it had flood
five days on the lime, the mixture became
immediately white and turbid, and foon pre¬
cipitated a white powder ; which, being fepa-
rated from the water, by filtration, and dried,
weighed 2y gr.
The fame quantity of fait of tartar, mix¬
ed with eight ounces and two drams of double
lime-water, that had Rood eight days on the
lime, became confiderably thicker and whi¬
ter than the former; and afforded rather
more than 7 grains of white powder.
The fame quantity of fait of tartar being
mixed with eight ounces and two drams of
the
PHYSICAL and LITERARY. 379
the double lime-water (d), which had flood
24 hours on the lime, gave eight grains of
a white powder.
It was obfervable, that thefe three lime-
waters retained the tafte of the lime, after
being mixed with the fait of tartar, and this
equally after precipitation, as before it.
Since the earthy powder precipitated by
thefe different lime-waters, proceeds wholly 9
or altnoft wholly, from the waters, and not
from the fixed alcaline fait ; * thefe experi¬
ments (hew, beyond doubt, that double lime-
water may contain thrice as much lime, as
lime-water made by pouring, on quick-lime,
512 times its weight of water.
IV. 1. Monday 24th December , at eight in
the evening, I poured upon a dram of frefh
calcined oifter-fhells, reduced to a powder,
520 drams of boiling water.
2. At
* What proves this, is, that the calcarious matter preci¬
pitated by mixing fait of tartar with lime-water, is greater
or lefs, in proportion to the ftrength and quantity of the
lime-water ; but not in proportion to the quantity of the
fait. Thus 12 grains of fait of tartar, mixed with four
ounces of ftrong lime-water, yielded as much of this matter,
as the fame quantity of this lime-water, mixed with s8
grains of the fait.
380 ESSAYS and OBSERVATIONS
2, At the fame time, I poured upon a
pound of the fame calcined (hells, 8 pounds
of boiling water,
3. Tuesday, at eleven before noon, I
poured fifty ounces of the lime-water N° 2,
on nine ounces frefh calcined oifterfhells 5
and, at eight in the evening, I filtered,
through brown paper, thefe three waters,
and put fixteen ounces of each of them in¬
to a bafon by itfelf 5 and, having placed the
bafons in a clofet, where they might be pretty
free from duft, I let them .ftand 19 days.
After this, I filtered the feveral waters through
brown paper, and having collected the earthy
crufts, and dried them well ; I found, that
N° 1. afforded very near four grains, N° 2,
near 12 grains, and N° 3, rather more than
3 3 grains,
Althg3 thefe three lime-waters had, at
the time they were filtrated, quite loft their
tafte; yet, obferving that N° 2. and 3. be¬
came turbid when mixed with fait of tartar,
I added eight grains of this fait to twelve
ounces of thefe two waters ; and the white
powder which was precipitated, when dried,
weighed juft one grain and a half*
Having
y f \ - v * : - - *
PHYSICAL and LITERARY. 38*
Having filtered the lime-waters of N° 2,
and 3 . into the fame bottle, before I fufpected
that any thing of die lime remained in them*
it became impoffible to know, which of them
afforded moft of the calcarious powder preci¬
pitated by the alcaline felt, or whether it did
not proceed wholly from N° 3.; in which
cafe, fixteen ounces of it m u ft have contain¬
ed 17 gr. of the earthy part of the lime, and
and N° 2. only 12 gr.
Since N° 2. and 3. were not quite free of
the lime, altho’ they had flood expofed £9
the open air 1 9 days, and had loft above |r
by evaporation 3 it follows, that the fureft
way of knowing the quantity of calcarious
earth, contained in lime-water, is to evapo¬
rate it, as Dr. Langrijh did * : and, if it be
objected to this, that all water affords fome
earth, when evaporated 3 the quantity of
this may be determined by experiment : tho’,
in many waters, it may well be negledted, on
account of its fmalnefs,
j
It has been argued that quick-lime muft5
after many repeated affunons of water, yield
as ftrong lime-water as at firft 3 becaufe, as
long as there remains any virtue in the lime,
the
•• v t e
f Pbyfical experiments pn brutes, p. 3 u
382 ESSAYS and OBSERVATIONS
the water will extrad it, and continue to do
fo, till it has taken up as much of the lime
as it can bear. But to this we cannot a-
gree : for, the’ there is undoubtedly a cer¬
tain degree of ftrength which lime-water can
never exceed ; yet, in order to communicate
to water, this degree of ftrength, flaked
lime may not only be infufficient, but repeat¬
ed additions of quick-lime may be neceffary;
unlefs perhaps a very fmall proportion of wa¬
ter is poured upon it. Quick-lime, frefh from
the fire, yields its virtues more eafily, than
when weakened by long expofition to the air,
or by many affufions of water : the water
mull extrad the virtues of the latter, while
the former, by a fort of explofive force of
its own, quickly impregnates the water. Nor
is it to be wondered at, that quick-lime, frefh
from the fire, fhould, at firft, impregnate
water more ftrongly with its virtues, than it
does afterwards. This Is as eafily conceived,
as that boiling water fhould extrad more of
the virtues of tea or coffee, than cold water.
1 he only difference is, that the menjlruum in
the latter cafe acts more powerfully, while
In the former the fpbftance to be extracted
affords
PHYSICAL and LITERARY. 383
affords its finer parts more readily, and in
greater abundance.
Upon comparing the experiments N° L
with thofe of N° III. and IV. it appears, that
the difference between the fpecific gravities of
different lime-waters and common water, is
much more than the weight of the calcari-
ous matter contained in thefe lime-waters :
there muff, therefore, be fomething elfe be-
Tides this earthy matter, which quick-lime
communicates to water, by which its weight
is increafed*. Perhaps quick-lime may alfo,
in fome other way unknown to us, alter the
* As lime-water, after its earthy part has been precipi¬
tated by an alcaline fait, continues to tafte ftrongly of the
lime ; it follows, that, befides this earth, it contains fome
more a&ive and fubtile part, to which its take and virtues
are chiefly owing : for we know that the calcarious matter
of lime-water, is perfectly infipid and void of any other vir¬
tue, than what all abforbent earths poffefs. This aftive and
more fubtile part of lime- water, feems to be feparated from
its earth by the alcaline fait, which ftrongly attracts and em¬
braces it. And hence lime-water mixed with fait of tartar,
does not lofe its tafte of the lime by being expofed to the
open air. Does not a folution of a fixed alcaline fait in wa¬
ter, poured on quick-lime, feparate this fubtile aftive matter
of quick-lime from its earthy part, by ftrongly attra£ling
it ? And qo not foap-leys confift of water and a fixed alcaline
fait united with this aftive part of quick lime, without any,
or almofi any, of its earthy part ?
334 ESSAYS and OBSERVATIONS
fpecific gravity of water. But, whatever
may be in this, it is evidently unreafonable to
deny that lime-water is as much fpecifically
heavier than common water, as the hydrofta-
tic balance, or other accurate experiments
fhew 3 becaufe we cannot account for this
excefs of gravity from any thing we know of
the contents of lime-water. This is no lefs
imphilofophical, than if, one was to doubt of
univerfal gravity, becaufe philofophers have
hitherto attempted, in vain, to account for
it. If we miftake not the matter much, the
contrary has always been the opinion of man-
kind, viz. that every well attefted fa£t is to
be believed, altho" we are ignorant of its
caufe, or cannot fhew the particular way in
which it happens.
Enough, it may, perhaps, be thought
more than enough, has been faid, to fhew
that the ftrength of lime-water is very diffe¬
rent, according to the different quantities of
water poured on quick-lime. However, I
mu ft be allowed to fay, that this point,
which has been difputed by my good friend,
is of that confequence, as to deferve to be
fully cleared up ; fince, to fuch as drink
lime-water, with a view to the cure of the
ft one.
PHYSICAL and LITERARY. 385
ftone, it is of no fmall importance to know,
how it may be prepared, fo as to have the
fureft and fpeedieft effects. And, as lime-
water, injefted into the bladder, will un¬
doubtedly diflblve a ftone lodged there 5
it is evident, that, after the bladder has
been accuftomed to the weaker lime-wa¬
ters, or to thefe even foftened with a little
fweet milk, the dilTolution of the ftone may
be much haftened, by injecting fuch as are
more ftrongly impregnated with the virtues of
the lime.
With regard to the lithontnptie powers
of oifter-fhell and ftone-lime water, I (hall
only fay, that, as in a variety of experiments
made during the courfe of ten years, I had
always obferved the fuperior efficacy of the
oifter-lime-water I thought it to no purpofe to
make a new trial : any one, who doubts on
which fide the truth is, may eafily fatisfy
himfelf. But, in making the experiment,
the calculi fhould either be immerfed in a
large quantity of lime-water, or elfe it fhould
be renewed upon them every three or four
days.
C C G
A P Tz
386 ESSAYS and OBSERVATIONS
Art. XIV.
Of the anthelmintic Virtues oj the Root of the
Indian Pink, being Fart of a Letter from
Dr. John Lining Phyfcian at Charles¬
town in South Carolina, to Dr. Robert
W hytt, Profejjor of Medicine in the U~
niverfty oj Edinburgh.
THERE is a plant, commonly
called, by the Carolinians , Indian
Pink , which grows in this province, the root
or which is ufed as an anthelmintic, and was
firft communicated to the Englijh by the In¬
dians.
The root is either given in powder, or an
infuiion is made of it in boiling water : but
the powder is moft effectual. When I give
the powder, I add fome rhubarb (a fufficient
quantity to keep the belly open) and a little
of fome of the effential oils, as the ol. rut .
fabm . or abfinth. To a child of three years
of age, 12 grains of the root in fubftance is
a moderate dofe : and I repeat it morning and
evening for fome days; ordering, at the fame
time.
PHYSICAL and LITERARY. 387
•time, a proper regimen. When the root is
given in infufion, 20 grains of it make a fuf-
ficient dole for a child of the fame age.
It has an advantage above all other anthel¬
mintics that I am acquainted with, as it is
lefs naufeous, and may fafely be given in
fevers without heating too much : likeways
children, when they awake in the morning,
may be deceived with it, by giving the infu¬
fion with a little milk, and a fufficient quan¬
tity of fugar, in place of tea. Tho’ it does
not always fucceed in expelling worms ; yet
I have obferved, that children's complaints
were remarkably relieved after having taken
it for fome days.
I fnall only trouble you with one fhort hi-
ftory, where I gave it the other day with fuc-
cefs. I was fent for to a Negro-child, about
four years of age, on the feventh day of a
continual fever : and, as I fufpefted that the
fever was kept up by the irritation of worms,
I ordered the following, that morning ; R.
aq. theriac. drach. ii. aq. font. line. Wfs. pufo.
rad . anthelmicz (for fo I called the Indian
pink) tart, regenerat . ana ferup . i. pulv. croci
anglic. gr. v. facch . q.f. M. fumat coch . unum
fecunda quaqne bora , Next morning, I ordered
388 ESSAYS and OBSERVATIONS
a repetition of the fame ; and, in the after¬
noon, when the child had a ftooi, 30 large
worms, the teretes , were at once voided ; and
that afternoon, the fever went intirely off,
and did not leturn. Next morning I repeat¬
ed the fame mixture j and, that day, the
child voided 9 more of the fame kind of
worms.
When too great a dofe of the powder or
infuiion is given, it has fome ftrange effedts,
which appear very foon after the dofe is ta¬
ken. Children become vertiginous, com¬
plain of a pain in and over their eyes, and
the mufculi adduffiores and abdudlores oculorum ,
feem to be greatly affedted, from their irre¬
gular adtions ; while the other mufcles of the
eye, fo far as I have had an opportunity of
pbferving, remain unaffedted. Thefe fym-
ptoms, however, foon go off ; and their re¬
moval may be haftened by giving fome weak
fpirituous liquor, to which volatiles or faffron,
or any of the warm effential oils, are added.
But, to prevent any of thefe bad effedts of
this medicine, fome gutts of the oils before
mentioned are added.
I
PHYSICAL and LITERARY. 389
• I have been the more particular in my ac¬
count of this medicine, as I imagine it may,
when properly introduced into pra&ice, be
of great ufe in faving the lives of many. It
has been, for many years, ufed in this part
of the world, not only by all the practiti¬
oners, but likeways univerfally by the plant¬
ers.
\
A R T.
S9o ESSAYS AND OBSERVATIONS
A R T. XV.
The Jiifiory of a Cure performed by large Dofes
of an alterative mercurial Medicine , com¬
municated to Dr, Plummer , by Mr .
George Dennistoun Surgeon in Fal¬
kirk.
A BOUT the month of December 1737*
±\_ a gentleman applied to me for cure : he
complained, that, for fome time pad, he
had felt pricking pains in feveral parts of his
body, efpecially about his fhoulders and fhin-
bones, which were now become intolerable.
Pie had dry fcurfy fcabs over the whole in-
fide of the thighs, the glands of both groins
were a little tumified ; and hard crufty fcabs
were here and there fcattered upon the fcro-
tum^ hips, and about the podex. From the fe,
and other circumftances, I had no reafon to
doubt that my patient's difcemper was the
venereal lues • upon which, I raifed a faiiva-
tion with mere. dulc. in the courfe whereof,
all the fymptoms gradually difappeared. I then
put him upon a courfe of the pil. JEihiopic.
and
PHYSICAL and LITERARY. 39s
and decodion of the woods; by which means*
he feeming to be very well, I flattered my-
felf that the difeafe was intirely eradicated.
He had no complaints for above twelve
months 3 but then he began to feel the old
pricking pains, efpecially in his legs 3 and, in
a fhort time, he difcovered a fweliing on the
mod prominent part of his fhin~hone, about
the bignefs of a walnut, the’ flat 3 with
fuch fcabs, &c. as were formerly mention¬
ed : and all this (as he told me) without rea-
fon to fufped a new infedion.
In fhort, he applied to me a fecond time,
and, having advifed with a phyfieian, very
eminent in his profeffion, he defired me to
put him upon a new courfe of mere. dulc. but
to give fuch fmall dofes, at fuch intermediate
diftances, as to raife the falivation very flow-
ly 3 and, when once railed to the quantity
of lib. iii. or lib. iv. in a day, to keep it up
at that rate, by now and then dropping in a
bolus, for two months at leaf!: ; and, at the
fame time, to annoint the node on his fhin-
bone with ung. mercurial. &c, I followed his
directions punctually; and, indeed, all the
fymptoms went gradually off, except the
forementioned node, which was little or no¬
thing
392 ESSAYS and OBSERVATIONS
thing altered, only he felt no pain in it : 1
was then ordered to give him the piL JEthi-
epic , and decoB . lignor . after the ufe of which,
for above a month, he began to feel fome
flinging pains in the node, and even through
the whole leg, which daily increafed. I
had read the hiftory of your alterative pills,
fome time before : and, judging they might
be more forcible than the pil. Mthiopic . in re¬
moving thefe fymptoms, and the remains of
the di he m per I hinted the fame to the Do¬
ctor, and he chearfully agreed to ufe the one
in place of the other. I fhall here obferve
that the firfl fai Nation was railed with ferup .
iv. of mere . dulc. and that he only fwaliowed
jerup . viih through the courfe of the other ;
by which it would appear that that medicine,
had by no means become familiar to him. I
prepared your pills precifely as directed in
Medical Effays vol. i. art. vi.; only inhead of
calomel , I took the fame quantity of mere .
dadc . and indeed of the fame kind with
which I had raifed the laft falivation : and,
having divided the maf$3 as is there alfo di-
refted j I ordered him to take three pills morn¬
ing and evening with a draught decoB < lignor „
after each dofe, and to drink plentifully of
th©‘
PHYSICAL and LITERARY. 393
the fame thro’ the day. This cotfrfe, with
a due regimen* he obferved regularly for a
month : but as he was quite wearied with
the tedious courfe he had formerly under*
gone; and, as he afterwards told me, was
refolved his difeafe fhould terminate foon,
either in death or recovery 5 he frequently
begged I would increafe the dofe of pills :
upon which I allowed him to take four,
morning and evening, but told him I durlt
venture no further ; and withal what quantity
of mercury they contained : he at the fame
time afked me, what would be the effedt of
over-doling them? I told him, I believed they
would either caufe him vomit, or raife a fali-
vation : this he pocketed up, as being figns
fufficient to know when to flop 3 in Abort,
as he had accefs to get the pills renewed at
my (hop when he pleafed, without my know¬
ing any thing of the matter ; he had taken
24 pills each day for the continued fpace of
fix weeks, without being attended with the
fmalleft inconvenience : and in that time the
erratic pains and node had intirely vanished :
but he afterwards made ufe of the pills, thoJ
in fmaller dofes. Having thus conquered his
difeafe by his ralhnefs * he triumphed as ha*
Ddd ving
394 ESSAYS and OBSERVATIONS
]
ving alfo conquered the too timorous caution
of his phyficians. Upon a calculation, I find
he had taken unc . xiv. of the alterative pills,
which may contain about unc . iii. of fweet
mercury, from the firft day of December
1739, to the firft of May immediately there-
after 3 but that he had taken unc . ix. (confe-
quently above ferup xv. of fweet mercury)
within the fpace of fix weeks without inter-
million. And ever fince he has enjoyed per-
fedt health. From this accidental experi¬
ment, I conceived fuch a good opinion of
thofe pills, that I have frequently ufed them
fince, in many different cafes ; and with
much fuccefs : I have found moft cutaneous
difeafes yield very foon to this remedy ; a-
mongft others, what is vulgarly called Sib-
bens , which rages in the moorlands near this
place : whether this diftemper is really a
pox, I fhall not pretend to fay ; only it is at¬
tended with the fame fymptoms : and I now
begin to think, that, if thefe pills are given
in fuch large dofes as before mentioned, in
which, I accidentally found there was no
danger 5 I don’t doubt, but moft of the di¬
feafes which ufually yield to mercury, may
be fubdued by this medicine. I fhall only
add
PHYSICAL and LITERARY. 393
add that I now omit the refna guajac. and
increafe the quantity of the gum ; and I
boil the lign . guajac . much longer than is di¬
rected in the Edinburgh Difpenfatory, which,
I am fenfible, makes the decoCtion much
ftronger.
Art,
S96 ESSAYS and OBSERVATIONS
Art. XVI.
4
A Defcription of the feminal Vejfels , by Ale¬
xander Monro, Student of Medicine in
the Univerfty oj Edinburgh.
%
THO’ all anatomifts agree, that the feed
feparated in the tefticle, paffes thro1
the epidydimis to rife in the vas defe¬
rens ; yet few have a right notion of even the
proffer tubes in which it is conveyed. I have
o ' ' J
luckily made quickfilver pafs farther in thefe
feminal veffels, and thereby brought more of
them into view, than I iee defcribed in any
anatomical book; as you may judge by the
preparations and pictures which I now fend
you, at my father’s defire.
De Graaf had formerly endeavoured, by
diffedtion, to unravel the epidydimis ; and
paints it as riling from the tefticle in fix or
feven branches, which join at its caput or
fir ft remarkable turn into one pipe, the nu¬
merous contortions of which form the body
£ t l v / f ; : •-1 ■ t ' * ■ i j t ' ; ; • • v J
f Df Fir, Organ, 7 ah. I. Fig. p ei Tab. 4. Fig. p
PHYSICAL and LITERARY. 397
•of the epidydimis , terminating at its other end
in the vas deferens .
This feems to have been overlooked, or
not well underftood, by mod: of the modem
anatom ills, who have differed widely, or
talked with uncertainty, about thefe pipes;
till of late, that the ingenious Dr. Haller , by
inje&ing quicklilver from the vas deferens , in
the manner propofed by my father in the
Medical EJJays and caufing it to pafs as far
as the teflicle, has been able to explain to us,
with greater accuracy, the ftrudure of this
intricate organ •f'* He agrees with DeGraaf
that the epidydimis , from the vas deferens to
its head, feems to be compofed of a fmgle
pipe, which he thinks might poffibly be un-
loofened, as De Graaf has reprefented ; but
does not affirm his having executed it. At
its head indeed, he could divide it into ten or
more vafcular cones, from which veffels go
out, that, after forming a network with com¬
munications, give off (freight pipes which
ieera to plunge into the body of the teflicle,
—His injeHion here generally failed, tho’ he
fometimes obferved, that it entered a few con-r
v olu ted
* Vol. v. Art. xx. § 29.
f Phil. Tranf, 494. § xi}8
ESSAYS and OBSERVATIONS
voluted tubes.— He mentions his having thrice
feen a veffel going off from about the middle
of the epidydimis towards the fpermatic cord*
which he imagines is a lymphatic .
That this accurate anatomifFs improve¬
ments, and the additions I am to make to
them, may be better underftood; I have firft
«
copied his elegant figure, and then fubjoined
fome others I caufed to be drawn of thofe
parts.
Tab. 3. fig . 1. from Dr. Haller .
A. The vas deferens .
B* The end or laft turn of the epidydimis .
C. Its body, as it appears when the exter¬
nal membrane is diffeded off,
D. Its head unloofened*
see. &c. The vafcular cones into which if
divides.
ffi The vafa efferentia, as he calls them.
gg. The network with communications.
hh. The ftreight veffels which feem to
plunge into the tefticle.
fig* 2a The tunica vaginalis of the te-
fticle is cut off, and the tefticle, injeded e-
pidydimis and fpermatic cord, are reprefent-
€d covered with their membranes#
A,
PHYSICAL and LITERARY. m
A. The ferpentine beginning of the vas
deferens .
B. The globus minors or laft turn of the
epidydimis , from which the fmall convo¬
luted veffel, C) which Dr. Haller fup-
pofes to be a lymphatic, rifes.- - If it
is fo, it has not the valvular ftrudture
common to thofe veffels; for I can caufe
the quick- filver to flow either way in it.
D. The corpus py rami dale.
E. The body of the epidydimis, where the
convolutions feen thro’ the membranes,
are larger than they appear in fig, i.
F. The head, globus major , or fir ft remark¬
able turn of the epidydimis „
G. Its rife from the tefticle.
In fig . 3. and 4. ' The tunica albuginea is
taken off from the ftdes of the tefticle, and
turned over upon the epidydimis .
A. The tunica albuginea .
B. The tefticle.
hh . Dr. Hallers ftreight pipes from which
ccc. The fmall convoluted tubes upon the
fides of the tefticle are continued.
dd. In fig . 4. Reprefents a number of them
upon the convex part of the tefticle, at
the greateft diftance from the epidydimis ,
Fig.
4oo ESSAYS
and OBSERVATIONS
Fig. 5. Reprefents the tefiicle drawn afun-
der in its middle from its convex furface to¬
wards the epidydimis .
Fig. 6. A fmall piece is in the fame man¬
ner feparated from the fide of it.
In both we obferve Dr. Haller s ftreight
veffels entering at hh ; and then dividing into
ecc inumerable convoluted pipes, which com¬
pote almoft the whole fubftance of the tefti-
cle.
dd. A number of them where the injecti¬
on has gone very far.
N. These preparations had been kept fe-
veral months in fpirits, and fo often handled
before the drawings were made, that many
of the injeded vefiels are defiroyed, and the
painter could not diftinguifh the membranous
partitions of the tefticle.
As many of the moil accurate anatomiftsy
and even Winflow *, have imagined, that the
body of the epidydimis is compofed of a num¬
ber of pipes. — — As Dr. Haller does not po¬
sitively affirm Siis having unloofened it. -
As the vas deferens is much larger than any
P*Pg
Exp. anat. traite de bas ventre. § 4,33.
I
TAB. in.
PHYSICAL and LITERARY. 401
•pipe in the epidydimis , and as it feems diffi¬
cult to conceive how the feed can be propel-
ed thro’ a tube fo finally fo much convoluted,
and of fuch a length as the (ingle one, which*
according to De Graaf , forms the epidydimis :
on thefe accounts, I think, there is reafon to
doubt this drudiure which he afferts, till we
have more fatisfying proof of it than has hi¬
therto been adduced.' — —Such the following
appears to be. If, in attempting to make
preparations like to thofe above defcribed, an
extravafation happens in any part of the epi-
dydimis , or if any of its convolutions are tied,
not a drop of the injection can be pdfhed
farther towards the tedicle than this extrava-
fation or ligature : and, if the epidydimis is
cut acrofs, while quickfilver is poured into
the tube fixed in the vas deferens , it fquirts
out only at one orifice in this cut part * which
is the plained and mod convincing demon-
ft ration of the body of the epidydimis , being
entirely compofed of a fingle tube convoluted
in a mod wonderful manner.
Tho’ my injection penetrated far into the
feminal pipes • yet dill we are unacquainted
with their origin. De Graaf * attempted in
Eee vain
* De vir, orgc p. 4 1,
402 ESSAYS AMD OBSERVATIONS
vain to difcover this by maceration in water *
nor have anatomifls fince his time been more
fuccefsful.
I have endeavoured feveral times to force
quick- fiiver from the fpermatic arteries into
the feminal veffels ; but, tho’ I made it re¬
turn by the 1 Dermatic veins, I could never
caufe it to pafs into thefe convoluted tubes.
This I attempted the oftener, becaufe of
the feeming probability of our being able to
determine, better in this than in other glands*
whether fecretion is performed in continued
cylindrical canals, according to Ruyfch , or*
by the intervention of follicles, with Mal¬
pighi us y fince we can feparate the parts of
the tefticle, without cutting, and even al~
mod without laceration.
Art,
PHYSICAL and LITERARY. 403
Art. XVII.
The Dijfedlion of a Woman with child ; and
Remarks on gravid uteri, by Dodlor Donald
Monro Phyjician at London.
Gentlemen,
THE few hifiories of difledions and fi¬
gures there are of gravid uteri , make
me imagine, that an account of what I ob-
ferved in one that fell under my examination,
illuftrated with a few figures which I took
from the fubjed itfelf, would not be unac¬
ceptable to you.
While I was at Edinburgh laft year, the
body of a woman, faid to be fix months
gone with child, was brought to the anato¬
mical theatre ; which my father defired me
to examine accurately, and particularly to en¬
deavour what I could to (hew the anadomofis
between the vefiels of the womb and thofe
% /
of the fecundines, if there were any Inch,
as Nortwyk * affirms there are, and Haller ,
in his Primee Linece 4*, feems to all edge ;
tho’*
* Hift. uteri human, p. i . § 7. and p. 2. § 83.
t § 830.
4G4 ESSAYS and OBSERVATIONS
tho’ in private converfation with this laft
named gentleman, when I was his fcholar
at Gottingen , he told me, that, what he had
wrote concerning that fubjedt, was upon the
authority of others, and not from his own
obfervation \ for that he had had three wo¬
men with child for fubieds, whofe bodies
he had injedted and diffedted ; but had found
nothing like an anajlomofis between the uterine
and fecundary veffels in any of them : fo that
he now believed there was no fuch anaftomofis
as was alledged.
I opened the body of this woman ; and,
at firft, imagined we had been miftaken a-
bout her being with child $ for the inteftines
came as low down as the ojfa pubis , and co¬
vered intirely the uterus : but, in turning
tip the inteftines, we were foon undeceived,
and faw the diftended womb. — - — -I then laid
bare the defeending aorta \ and, having fix¬
ed a large pipe of a fyringe into it, and
warmed the uterus well, by pouring warm
water upon it, and by keeping afterwards
applied to it fpunges filled with the fame 3 I
injected hot oil of turpentine, coloured with
very fine powder of vermiilion, into the
f, ffltg 1 and, pfter that, a coarfer injedtion
PHYSICAL and LITERARY. 40$
of melted tallow, dilated and coloured with
part of the former injedting materials.- -
My father then demonftrated to his pupils
the parts in their natural fituation ; and I
made the fketch of the uterus , as reprefent-
ed in tab . iv. where the containing parts
AAAAA, being laid afide, you fee the womb
BBBB, with its fundus , raifed higher in the
right fide than in the left CCC, the larger
branches of the arteries on the forefide of the
womb of a very ferpentine form, and ana-
ftomofing with each other 5— — -DD, the
round ligaments ; EE, the Fallopian tubes
fixed to the uterus , a good way below the
fundus , infiead of being fixed to its angles,
as they are in an unimpregnated womb ;• — F,
the urinary bladder, which, in this fub-
jedt, rofe a good way above the pubes> turn¬
ed down over it with a piece of the integu¬
ments ; — G, the left ovarium.
Next day, the fubftance of the womb
was cut thro’ cautiouflv, a little farther fore-
wards than the round ligaments ; and, when
the incifion had penetrated into the uterus ,
a fubftance appeared which feparated quite
eafily from the more external parts, by being
gently prefled with the finger 5 and, by pufh-
ipp?
40 6 ESSAYS AND OBSERVATIONS
ing the finger alternately upwards and down¬
wards, fo much of this fubflance was fepa-
rated from the womb, as to allow a probe-
pointed pair of fciffars to be introduced for
enlarging the incifion, parallel with the fide
of the uterus , I then faw that this fubflance
was a villous membrane, which feparated al-
moft of itfelf from the cut fides of the womb,
when we attempted to raife them. In doing
of this we could not obferve any tearing of
veffels or fibres, except in fome places where
fmall convoluted arteries were broke off* from
the forepart of the uterus to adhere to this
villous membrane. In this manner, this
outer lamella of the chorion was every where
feparated from the forepart of the uterus ,
which was cut thro* with a pair of fciffars all
around its fundus and edges, as low down as
the ojfa pubis , and was turned down over thefe
bones.
The uterus was, as near as I could judge,
about the thicknefs of an unimpregnated one:
fome of the gentlemen who were prefent at
the diffedion, thought it was thicker, and o-
thers, that it was thinner.
The fubflance of the v/omb was compo-
fed of its firm flrong outer membrane which
is
PHYSICAL'and LITERARY. 407
is a continuation of the peritoneum : this ad¬
hered by a cellular membrane, thro’ which
a number of arteries ran, to a red colour¬
ed fubftance, which was about one half
the thicknefs of the womb, and had a mu-
fcular appearance ; but I could not obferve in
it any real mufcular fibres, laid in regular
fir at a — Within this there was a whiter co¬
loured fubftance, which, on ftretching, ap¬
peared plainly to be a cellular membrane,
with its infide fmooth and polifhed; but with
a cellular appearance whenever it was ft retch¬
ed, by endeavouring to raife it from the fub¬
ftance of the uterus. : for the internal very-
thin membrane, which covers the infide of
the womb, and is continued from the exter¬
nal cuticida , is fo fine, that it is fcarce to be
diftinguifhed. Numerous veflels, both arte¬
ries and veins, ran every where thro’ this cel¬
lular fubftance.
In the middle of the cut fides of the ute-
rus , the empty veins were of a great fize,
in companion to what the arteries, diftended
with inje&ion, were.
On the internal furface of the part of the
womb which was turned down over the pubes ,
convoluted arteries were feen j and fome ori¬
fices
4o8 ESSAYS and OBSERVATIONS
fices of veins appeared. The outer lamina of
the chorion , was fcabrous, fucculent, fomewhat
villous, of a pale flefhy colour, and not at
all tranfparent. The convoluted arteries
which I formerly faid had adhered to it,
when the womb was feparated from it,
were taken off with a pair of differing for¬
ceps, without any difcernable tearing of fi¬
bres. Crofs incifions were then made into
this cuter covering of the ovum , and it was
laid to a fide, when we faw the fecond lamel¬
la or clear tranfparent proper morion , which
feparated almoft of itfelf, from the outer
membrane ; they being only connected toge¬
ther by a very fine and tender cellular fub-
ftance. This internal lamella or proper cho¬
rion being cut thro’, the fine amnios appeared,
thro’ which was feen the foetus fwimming in
its waters.
In Tab. vi* fig. i. are reprefented AAA,
the edges of the cut uterus , with large ob¬
long orifices of the cut empty collapfed veins,
and of the irnaller round injected arteries;—
B, the forepart of the uterus turned down be¬
tween the thighs;— CC, part of the outer la¬
mina of the chorion-,— DD, part of the inner
lamina of the chorion ; ™E, the amnios un*-
opened.
PHYSICAL and LITERARY. 409
opened, thro" which is feen the foetus in its
waters.
The membranes being all cut thro7, and
the waters let out, we more plainly obferved,
as in Tab. v. fig. 1. the foetus A, with its
head downwards ; B, the navel-llring twill¬
ed round its neck;— the placenta CC adhering
to the back part of the womb, with the mem¬
branes DDE), lying folded upon its edges;
and the cut Tides of the uterus EEE, where
the orifices of the veins and arteries appear,
> *. t
as in the figure formerly referred to;— F, the
vena cava G, aorta defcendens H, the
inferior mefenteric artery, to fhew how high
the fundus of the womb was railed.
That a comparifon of the fituation of
#
this foetus , with others, might be made ; I
fketched in miniature the outlines of Bldlod s,
and Albums s figures. Fig. 2. of Tab. vi. is
Bidlocs , where the foetus lies in a bended
pollute, with its head uppermofl, and its
placenta adhering to the forepart of the womb.
And, fig . 3. of the lame table, is copied
from Albinus , where the foetus is with its
head more perpendicularly downwards than
in my fubjedt ; and no more, than the edges
Fff o*
4io ESSAYS and OBSERVATIONS
of the placenta adhering to the back part of
the uterus , can be feen.
W e fought diligently for an allantois ; but
could fee nothing that bore any refemblance
to it.
The following day, tallow diluted with
oil of turpentine, was thrown into the umbili¬
cal arteries towards the placenta ; and fome
of the fame materials, coloured with rad.
anchufce , was injected into the umbilical vein.
Tallow, diluted with oil of turpentine*
and coloured with verdigreafe, was likeways
thrown into the uterine veins, after its cut
edges were all tyed.
The foetus being taken out, we fa w how
far down the placenta adhered to the womb*
as in Tab. v. Jig. 2. where A A, is the low¬
ed: part of the placenta , with fome of the
membranes turned upon it ; — BB, a duller
of finufes, which appeared where thefe mem¬
branes had been taken from $— C, the entry
to the cervix uteri D, a fhare of the
forepart of the uterus turned down.
Upon taking the uterus out of the body,
and opening the back part of the vagina ,
there was, as in Tab. iv. jig. 3. A, a confi-
derable part of the cervix uteri very little
diflended 5
PHYSICAL and LITERARY. 411
diftended ; and the os tine re B, appeared
like a' (mall rima, befet all around with a
glandular ring, which was filled with a thick
mucus.
After this, the upper half of the pla-
cent a was feparated from the womb, to which
it adhered, by a cellular membrane of a
ftronger appearance than what connected the
womb to any other part of the ovum .
Extravasated injection of all the four
different kinds, was found between the pla¬
centa and uterus , the greateft part of it,
however, was of the vermilion injection,
that had been thrown into the defcending
aorta . Tho* the extravafated injedtion had
made its way into the cellular fubftance both
of the uterus and placenta ; yet not one fingle
velfel of the placenta was filled with any of
the injedtion that came from the uterus > nor
was a veffel of the womb filled with that
which came from the fecundtnes,— In fome
places where there was none of the extrava¬
fated injedtion adhering to the placenta \ I
obferved that it was covered with the outer
chorion ; and fome arteries broke off from
the womb, adhered to it, but were taken a-
way without laceration.
Most
4.12 ESSAYS AND OBSERVATIONS
Most of the apertures commonly called
Jinujes , were full of the green injection; and
fome few of them had a very little of the
vermilion in them. The internal membrane
of the uterus was extended over part of each
of their orifices5 and there formed a fort of
valve.— Some of thefe orifices were fo large,
as to have allowed one's little finger to have
been put into them ; while others were fo
final!, as fcarce to admit the point of a probe :
and there were of all the different fizes be¬
tween thefe.— The veins continued from
them were of a confiderable diameter ; but
• V.. J
not fo large as the Jinufes themfelves.
The extravafation having made the conti¬
guous furfaces of the placenta and womb of
my fubjed lefs diflind than I could have
wiflied ; I drew fmall figures of thefe parts,
from Albinus s elegant large original ones.
Fig. 4» of Tab. vi. is the placenta, exhibited
with its furiace contiguous to the uterus ip.
view; where the engraver has not done ja¬
il ice, in reprefenting the monticuli and Juki
of the placenta .
Fig. 5. is better copied, where the oviform
figure of the uterus of his fubjed, ftrikes the
eye* with the orifices of the cut veffeis in its
fpbftance.
PHYSICAL and LITERARY. 413
fubftance; and the infertion of the round li¬
p-aments are feen, at AA. The numerous
Jinujes fufficiently (hew where the placenta ad¬
here to it. To fome few of the valvular
membranes of thofe Jinujes , I have put a\
and b is placed near to what reprefents their
orifices cc, point fome of the ferpentine
fmall arteries ; — -D, the valvular protuberance
at the back part of the cervix uteri 5 —e, the
gs tincae with part of the vagina opened.
Tab. vii. jig. 1. Is the appearance which
a part of the uterus of my fubjedt had, where
the fjiufes were not diftended ; and fome of
the ferpentine uterine arteries were diftin&ly
feen.
Fig. 2. A Jinus A, with its valvular mem¬
brane cut away, when the orifices of three
veins B are feen.
Fig. 3. The three veins flit open, till where
they meet in one trunk.
Fig. 14. Is a copy of a little piece of Al¬
bums $ figure, where the finufes and ferpen¬
tine arteries are reprefented of the natural
fize.
The fpermatic vein appeared of fuch a
monftrous fize, and fo much larger than the
fpermatic artery, that I differed and made a
draught
ESSAYS and OBSERVATIONS
draught of them, as reprefented in fig. $e
where the vein AA, '.and the artery BB, ap¬
pear twifted frequently round each other; and
fometimes as if the artery entered into the
vein;— C, the fimbriae of the tuba Fallopi -
ana-, — D, the ovarium,— E, part of the liga -
mentum latum .
That others may judge how long my fob-
jedt had been with child, 1 have added the
outlines of the foetus of the natural dimen-
lions, in fig. 6 .
Thus, Gentlemen, I have fairly related all
that I obferved in the dififedtion of this pre¬
gnant uterus ; and beg leave to be allowed to
add fome few remarks upon the whole.
From the figure of the womb I difTedted,
compared with thofe of Cowper , Nortwyk ,
Albums, Hunter and others, it appears, that
the fundus of the impregnated womb, is al¬
ways greatly extended upwards, in the time
of gravidation, by which the round liga¬
ments and Fallopian tubes, which are inferted
into the angles of the unimpregnated womb,
are then much lower than the fundus : for,
in my figure, thefe ligaments and tubes, are
almoft one third of the length of the womb
lower
TAB
4.
+
»■
4
X
4
-l
T AB . AT.
L
rP A ~n> TTT
*
PHYSICAL and LITERARY. 415
lower than its top: and Ve [alius Nortwyk *j*
and others, have obferved, that the further
advanced the woman is in her pregnancy, the
lower they defcend.
The uterus, by impregnation, maybe for¬
ced into different fhapes. My figure and that
of Bidloo , which refemble each other greatly,
fhew, that one fide of the womb may be
raifed much higher than the other. Vater
and Albinus , have painted the uterus as oval ;
and Nortwyk has reprefented it flat at top :
but, as all thefe three Gentlemen’s figures
were done from wombs which were previous¬
ly taken out of the body, we can form no
judgment of the fliape of the womb from
their draughts ; becaufe when the uterus is
taken out of the body, it aflumes a different
ihape, according to the manner in which it
is laid down. In Mr. Hunter s elegant figure,
which was taken from the uterus in Jitu, the
womb is more oblong than in mine. And in
two other pregnant women I faw differed,
the one feven, and the other four months
gone with child ^ the uterus was in both more
globular
* lib. 5. cap. 17.
f Hilt. Uteri, pars 2. § 77. p. 70.
4i 6 ESSAYS and OBSERVATIONS
globular than in the prefent fubjedt. Pofii-
bly the figure of the womb may gradually
become more oval, as the woman approaches
to her time. The part likewife to which the
placenta adheres, or the different fituation of
the child, may caufe great Variety here.
The ftrong outer membrane and cellular
one immediately within it, did not feern in
any of the pregnant uteri I faw diffedted,
*
or by the accounts of any authors, to have
been much altered by the great diftenfion
they underwent.
Heifter % Nortwyk T, and Mr. Hunter,
obferved the fame mufcular appearance un¬
der this outer cellular membrane, as I did
a
without any regular layer of fibres ; as
Ruyfch has defcribed and painted nor could
I obferve any fuch regular fibres in a woman
who died a few hours after child birth, whofe
body I difledled while I was in Mr. LeCaf s
houfe at Rouen , tho’ Nortwyk || feems to
think, that if they are to be feen in any ute¬
rus j
* Anat. Compend. Tom. 2. p. 80.
f Hi ft. Uteri pars 2. § 87. p. 106.
t Advers. Dec. sii. Tab. 3. FW. i.
} Hill. Uteri pars 2. § 87. p. 107*
PHYSICAL and LITERARY. 417
fus> it mufl be in fach a one. Some few fi¬
bres there were, that went in an irregular,
tho’ fomething circular manner; which, with
the help of my differing knife, I could have
carved into a very pretty mufcle* Authors
have differed much about this mufcle 3 fame
affirming that they have feen it, while others
have denied that any fuch thing ever exifted.
Thefe different opinions are all taken notice
of, and quoted, in Boerhaave s PraeleH . pu¬
blished by Haller 3 Vol. v. § 664* to which
book I (hall refer you.
I have already mentioned, the womb’s be-*
ing much about the thicknefs of an unim¬
pregnated one : this however is not always
the cafe 3 and authors have differed vaftly in
their opinions in this point : fome alledging,
that the uterus is always thicker 3 others that
it turns thinner 3 while others have affirmed,
that it does not alter in its thicknefs by im¬
pregnation. This great difference of opini¬
ons, muff have been owing to the different
uteri which have been examined. As Dr.
Nortwyk has quoted the paffages of different
obfervators concerning this difpute 3 I Shall
refer you to his Hytoria Uteri % for their fen-*
G g g timents
* Pars 1, $ 5>o,
4i8 ESSAYS and OBSERVATIONS
I
timents about this matter ; and only obferve,
that Dr. Smellie , Mr. Hunter , Mr. McKenzie
and others, who pra&ife midwifery here, and
have had occafion to fee a good number of
impregnated wombs, are of opinion, that
in. genera!, the uterus does not alter much in
its thicknefs by being diflended; tho’ fome-
times it is found thicker, and fometimes thin¬
ner, than ordinary : and in a collection of u-
teri in Dr. Smellie ’s poffeffion, there are
wombs which feem to favour all the three dif¬
ferent opinions. One of the wombs in this
collection, is remarkably thin, not being a-
bovethe third part fo thick as an unimpregna¬
ted uterus generally is. If I was to form a
judgment, from the few gravid uteri I have
feen, I would be inclined to think, that if the
womb alters in its thicknefs at all, it rather
turns thinner \ but the difference is fo fmail,
for the moft part, that it is difficult to form a
judgment about the matter. I ought howe¬
ver to obferve, that the gravid uteri will be
considerably thicker during life, when they
are full of blood, than thev are in dead ho-
dies, where the veffels are all collapfed. The
difference was confiderable, in the bulk and
thicknefs of the womb, before we injected
the
PHYSICAL and LITERARY. 4x9
the veins, from what they were, after we had
filled them with tallow.
By fome few of the finufes having a little
of the red injedtion in them, it may be con-
jedtured, that fome of the final! branches of
the uterine arteries opened into them : but I
could not obferve their orifices ; and they
themfelves were fo fmall, that I only faw one
or two fmall twigs running along the mem¬
brane, that lined fome of the finujes .
Since, neither in this fubjedt, the leaf!:
drop of either the injedtion that was thrown
into the arteries or veins of the mother; nor
in another woman, who died when four
months gone with child, whole uterine ar¬
teries I injedted with coloured tallow; any of
the injedtions were found in the fecundary
vefiels, tho’ a great deal of injedtion, in both
fubjedts, was found extravafated between the
placenta and uterus ; I muft be of opinion,
that there is no anaftomojis between the uterine
and fecundary vefiels ; and I could eafily fee,
how the extravafated tallow, injedted with
force, could make its way into the cellular
fubftance both of the placenta and womb.
Such ferpentine convoluted very fmall ar¬
teries, which Dr, Albinus has taken notice of,
and
420 ESSAYS AND OBSERVATIONS
and which I faw likewife, in this fubjed, on
the inner fur face of the womb, are not to
be obferved in any other organ of the body,
fo far as I remember.
Nothing remarkable was obferved in the
membranes of the ovum, more than what is
mentioned by the accurate anatomifts Albirus
and Haller : but Mr. Hunter obferved a num¬
ber of veins going from the uterus in conti¬
nued trunks, into the fubftance of the outer
lamella of the chorion , in a pregnant woman
he drfiedted, and whofe veins he had previ-
oufly injected with yeliow wax ; thefe he has
delineated in one of his figures, which will
foon be published. We could obferve none
of them in our fubieCt , but then, all the
forepart of the uterus was feparated from the
outer lamella of the chorion , before the veins
were injeded. Tho’ Mr. Hunter obferved
veins, he could not fee one artery, continued
from the womb to the chorion ; and the arte¬
ries of his uterus had been filled with injecti¬
on, as well as the veins.
In five of the fubjeds mentioned by my
father, in Medical EJJays two of which I
fyw, the placenta adhered to the forepart of
the
( , • ». ,
fV oh 2. Art. q.
PHYSICAL and LITERARY. 421
the womb ; while in our prefent fubjedf, and
thofe of Vater and Albums, the placenta was
fixed to the back part of it, and Dr. S nielli e
allures me, he has found it attached to the
os uteri . I think therefore it is plain, that
there is no particular part to which we can
fay the placenta is always fixed : from which
it may be juftly concluded, that the chorion is
not all equally capable of being placenta ; and
that the placenta does not owe its exiftence to
the energy of any particular fpot of the
womb 5 but that it is an original part which
adheres to whatever place, not only of the
womb, but of the Fallopian tubes * or abdo¬
men, -f* it happens to be contiguous to $ where
it caufes a confiderable flow of liquors, by the
abforbing powers of its veffels ; in the fame
way as the fucking of the nipple is the mod
effectual way of caufing a flow of milk to
the breafts. Thus the part of the human
womb where the placenta is applied, has its
extreme veins enlarged into Jinufes : and the
fmooth furface of the womb and its cornua
t
in cows, is raifed into glandular-like bodies
where each placenta is placed. Tuo*
* See two examples of this in De Graaf de mulieT. orga-
nis, cap. xiv. quoted from Riolan.
•J- An example of this, in Hip. de VAcad. des Sciences 171.6,
422 ESSAYS AND OBSERVATIONS
Tho* the contrivance of the blood re¬
turning from the foetus being poured into
Jimifes , is a very good precaution againft hae-
morrhagies ; yet the veins of the womb that
communicate with thofe Jtnufes , being fo
large as they are, one would think, that
more frequent haemorrhagies might happen
at delivery, was it not for the oblique man¬
ner in which the moft internal coats of the
womb are placed by way of valves over the
orifices of thefe Jinufes 3 fo that whenever the
womb collapfes or contrafts, thefe orifices
are aim oft inti rely covered by thefe mem¬
branes.
The oblique fituation of the foetus , the
erect, or what is generally called the natural
one, in the two I faw formerly, the tranf-
verfe one of Nortwyk and Cowper , perfuade
me, there is no determined fituation for a
foetus , as is commonly thought 3 but that it
may change places in its flirtings* as women
generally feel.
It has long been the received opinion, that
foetufes are moftly placed in the womb, in
what is called the eredl or natural fituation 3
that is, with the child’s forepart towards the
mothers belly 3 its head uppermoft, and re¬
clined
PHYSICAL and LITERARY. 423
dined forwards and downwards, and that in
the laft months of pregnancy, or immedi¬
ately before birth, the head, by its weight,
falls down towards the os uteri , fo that the
face of the child is turned towards the os fa-
crum of the mother, and in this manner is de¬
livered. All this account, both of the child's
pofition, and falling down of the head, I mufc
doubt of ; for, when I attended courfes of
midwifery I examined a great number of
women, in all the different times of pregnan¬
cy, from fix to nine months gone with child,
and in the greater number of them I felt the
head down ; and Dr. Smellie and Mr. Hunter
affure me, they have generally obferved the
fame thing : fo that this feems to be rather
what ought to be called the natural fituation.
If the child be fometimes in the erect lit na¬
tion, and its head falls down, I cannot think
that this change of pofture is owing to its
greater weight at this, more than at any
other time ; for, the head of a foetus is
proportionally larger and heavier, the younger
it is: but to the child, thro' a natural inftindt,
endeavouring to avoid the preffure which
its head would futter by the contraction of
the bottom of the womb, and the detrufion
of
424 ESSAYS and OBSERVATIONS
of the diaphragm during labour- pains, and
that, by being turned, its feet may act with
advantage, by pufhing againft the fundus li¬
ter i, to afiift the delivery.
The enlargement of the veins of the
womb during pregnancy, is really furprifing,
as may be judged by obferving their tranfverfe
fedtions in their collapfed date, as reprefent-
ed in the cut edges of the womb 5 fee Tab.
iv. and v. and by the fize of the fpermatic
Veins, in Tab. vii. fig . 5. I ought however
to obferve, that the trunk of the vein is here
represented lefs than it fhould have been 5 for
when the womb was cut out of the body,
fome of the injection was, by accident, pufh-
ed out of the veins, before the figure was
made. The fituation of this vein and artery,
may let us fee, how eafily Arantius ^ and o-
ther anatomifts, before the injedting art was
found out, might imagine the artery entered
into the vein ; that the arterious and venous
blood might be blended together before they
reached the womb. Injediions plainly fhew,
there is no fuch uncommon anafiotnofis be¬
tween the vein and artery.
* Arantius de foetu, eap, iii. p, jr.
PHYSICAL and LITERARY. 425
. The womb, by being diftended, preffes
on the iliac veins, and makes a difficulty to
the blood returning from the lower extremi¬
ties, and even to the blood returning by the
branches of the iliac, from the womb itfelf,
long before the uterus has rofe fo high as to
prels upon the fpermatic vein : is not then
this difficulty of the blood’s returning by the
iliacs, the caufe of the vaft difteniion of the
fpermatic veins during gravidation, as well as
it is often the caufe of the oedernatous legs3
and i welled labia pudendorum> at that time?
H h h
A R Ta
4,
©
426 ESSAYS and OBSERVATIONS
Art. XVIII.
Additional Obfervations on Gravid Uteri, by
Alexander Monro, Student of Medicine
in the Univerjity of Edinburgh.
Gentlemen,
HAV I N G wrote to my brother a few
obfervations which I had made in exa*-
mining a gravid uterus ; he defires me to add
fuch of them, as I thought might be a pro¬
per fupplement to the paper which he fent
you lately on this fubjedt.
The woman I diffedted was about forty
years of age, had born four children, and
was faid to be five months gone with child *
her uterus being almoft as large as in my bro¬
ther’s fubjedt, tho’ more of an oval fhape,
with the forepart of it contiguous to the peri¬
toneum.
Having obferved fo far haftily, I was o-
bliged to remove it from the body.
The os tincae , then feen from the vagina ,
was confiderably larger, and the cervix uteri
was
©
PHYSICAL and LITERARY. 427
was diftended lower down than is reprefented
in your Tab. v. jig. 3. which poffibly might
be owing to this woman's weaknefs, and to
the number of children which fhe had born,
A liquor, of a thicker confidence than
the oil of turpentine and Vermillion which
my brother made ufe of, being injected into
the hypogaftric arteries, filled the fpermatics,
and a confiderable artery in the round ligament.
The joining of the trunks of the two former
upon the fides of the uterus was fo large, that
it was impofiible to fay, from which of them
the branches diftributed to its fubftance were
. derived. The right fpermatic was fmall, but
the left was as large as a goofe quill ; the
hypogaftrics being of a middle fize betwixt
the two.— By blowing air into any of the
veins, we had fufficient proof of their mon-
ftrous fize, and of their numerous and very
large communications; the whole uterus be¬
ing at once inflated. — Correfponding to the
artery before mentioned in the round liga¬
ment. , I obferved a large vein in it, which pro¬
bably difcharged itfelf into the external iliac.
When the uterus was cut open upon its
fore part, near three fourths of its thicknefs
had plainly the appearance of a mufcle; the
fibres
428 ESSAYS and OBSERVATIONS
fibres being of a pale red or flefh-colour : and
when part of it was boiled in water, we
could not have diftinguilhed it fprn any other
piece of boiled flefh ; moil of its fibres then
feeming to run obliquely from the cervix to-
wards the fundus ; others appearing tranfverfe.
To which if we add the known fenfibility
of the womb, and its ftrong and hidden con¬
traction at birth, we have enumerated all the
effentiais required in the constitution of a
mufcle.
? *• ♦
As the internal cellular, or rather hi ecu-
lent fungous membrane of the womb, efpe-
daily where the placenta is fixed, is of a con-
liderable thicknefs; I cannot conceive, how
any thing like to an orbicular or radiated mu-
fcle could ever be aliedged to be feen upon
its inner fide, .without diflfeCtion.
The placenta and f etus were fituated near¬
ly in the fame manner, as is reprefented by
Bidloo ; a fmall Sketch of whofe figure is in
your 'Tab. vh jig . 2.: the/ poffibly the fitua-
tion of the foetus might have been altered,
by our having carried the uterus above half a
mile before we examined it.
The liquor amnii was of a clear brown co¬
lour s upon adding oil of vitriol , or oL tart .
p, d*
PHYSICAL and LITERARY. 429
p. d . to it, no remarkable change could be ob-
ferved : which proves that it contains little
ferous or urii us ; for the oil oj vitriol would
have coagulated the former, and the latter
would have betrayed itlelf upon the addition
of the fixed alcali.— — When it was brought
o
to a boiling heat, it threw up a thin whitiih
fcum ; and an ounce of it boiled dry, left a -
bout a fcruple of what appeared to be a fe¬
rous coagulum .
We could not obferve any thing like an
allantois : and, when the urachus was after¬
wards examined, it neither allowed air, wa¬
ter, or quick- filver, to enter it from the blad¬
der ; tho’ I have feen it pervious for an inch
or more in children, born at the full time.
The cervix uteri being now cut open ; the
whole inner fide of it was covered over, efpe-
cially near to the os tinea, with clufters of
veficles, fome of which were of a confide-
rable fize, filled with a dark brown-coloured
mucus ; and fmall orifices, containing the
fame kind of liquor, appeared in their in-
terftices.
When the placenta was taken off, the in¬
jection, which had been thrown into the hy-
pogafcric arteries, was found extravafated be¬
twixt
430 ESSAYS and OBSERVATIONS
twixt it and the uterus $ many lumps of the
wax being, as it were, wedged into the hab¬
it an cc of th t placenta, without having enter¬
ed any of its veffels, — -We then faw many
final! ferpentine arteries with their orifices o-
pening upon the internal membrane of the
uterus 5 and other, generally larger* convo¬
luted arteries, whofe extremities we could
not as yet obferve, appearing prominent in
the interfaces of cavities filled with the wax 5
and which, in the foregoing paper, are men¬
tioned under the name of finufes : the real
ilruclure and Situation of which, being little
underftood, tho’ often talked of, I finall re¬
late all that I obferved in this fubjedf ; and
then, by comparing it with the common de~
fcription, we may better underftand what
has milled mod anatomifls.
The finufes are feen without any previous
diffedion upon the inner fide of the uterus ,
chiefly where the placenta has been fixed $
for there are but few of them, and thefe ve¬
ry fmall, in any other part of it.—Their fides
are membranous, that, next to the cavity
of the womb, being in each very thin, with
a large orifice in it.— They can be readily dif-
tended, by blowing air, or injecting a li¬
quor
PHYSICAL and LITERARY. 43*
.quor into the veins 3 or they may be filled
from the arteries, tho’ with much greater
difficulty, as happened in our injection: when
ftretched, they appear of a fpheroidal ffiape ;
and, the diameter of their orifices being lefs
than that of their cavities, we may give
them the name of Jinufes.— Upon diffedli-
on, we obferve arteries opening, at leaf!:
into fome of them, as I fhali afterwards
prove, and confiderable veins are continued
from all of them 3 the veins and Jinafes ha¬
ving all large communications with each o-
ther 3 and, tho’ fome of the finufes may have
only two or three fmall veins opening into
them, yet, in general, the diameter of the
veins continued from them, is not greatly in¬
ferior to that of the fin us .
Since, from this defcription, it appears,
that thefe cavities are only the fomewhat di¬
lated extremities of the branches of the veins 3
we may account for their formation, from
the more than ordinary difficulty there is in
the return of the blood from the gravid ute¬
rus 3 which being therefore accumulated,
mu ft ftretch all the veins greatly, but fuch
parts of them moft as refill: the leaft : confe-
quently their extremities which are only co¬
vered
432 ESSAYS and OBSERVATIONS
vered by the lax internal cellular membrane
of the womb, will be moft dilated, or put
on the appearance of finufes ; and this effedb
will be moft confpicuous where the greateft
flow of liquors is, that is, at the place where
the placenta is attached to the womb; as my
brother has juftly remarked.
If we compare the above defcription with
the common notion of a Gnus, we (hall find
they differ widely.*— They are generally de¬
fined to be large cavities in the middle of the
fubftance or fie (by part of the womb, that
have fmall branches of arteries and veins o-
pening into them, with canals, whofe dia¬
meter is confiderably lefs than that of the
Gnus, running obliquely thro' the fubftance
of the womb to open upon its inner fide.-—
But fince, after a diligent fearch, no finufes
S.
of this form could be feen in this fubjedt ;
as neither my brother nor the accurate Albi-
nus paint or defcribe any fuch ; and, as the
ingenious and diligent Dr. Haller pofitively
affirms, in one of his lateft works that af¬
ter repeated experiments, he could not oh-
ferve them ; it feems probable, that the
trunks of the veins have been miftaken for
finufes; and their branches; for canals opening
into
* Prim. Lin. phyf. § 804,
PHYSICAL and LITERARY. 433
into the cavity of the womb ; nay, a late
learned author applies thefe names of finufes
and canals, to the trunks and branches of the
veins painted in Albums § 7th table of the
gravid uterus .
The exiftence of finufes and canals be‘ng
then imaginary, and the cavities which we have
defcribed under the name of finufes being in-
tirely the creatures of impregnation, and not
to be found in the uterus virgincus ; or being
at any rate, from the fize of their orifices, un¬
fit receptacles of the blood ; we cannot
furely account for the menftrual flux or any
other phenomenon from fuch a ftruCture.
As the finufes were filled by our coarfe in¬
jection, thrown into the arteries, I imagined,
that, by a careful difleCtion, the openings of
the arteries into them might pofiibly be ob-
ferved ; but, I found more difficulty than I
expedted, from the fize and very large com¬
munications of moft of the finufes and veins.
Near to the edges of the placenta , where
they were not fo frequent, I was lucky e-
nough to difcover, with certainty, feveral ori¬
fices of arteries, fome of which were of a
confiderable diameter, opening direCtly into
the finufes : and fince none of the anatomifls
I i i have
434 ESSAYS and OBSERVATIONS
have painted or defer ibed thefe openings, tho*s
in the imaginary ftru&ure of the Jinufes , they
are fuppofed \ 1 have caufed a few of the
mod diftind to be reprefented in Tab. 7.
jig. 7. where A reprefents the inner furface
of the womb, to which the edge of the
placenta had been fixed ^ — ib, two fmall arte¬
ries appearing after having pierced the muf-
cular fubftance ; — ccd , their ferpentine and
fpiral turns their openings into the f mu -
j'es 5 which were plain beyond difpute, when
the wax was taken out of the Jims , and the
artery gently preffed, the jams being again
in part filled from it, as is reprefented at
f. w. Nay, it is evident, that the arteries had
communications with the : Jinufes alfo in my bro¬
ther's fubjed ; fince the placenta was covered
over with the extravafated oil of turpentine
and vermilion, which wras injpded into the
aorta defeendens ; and which therefore feems
to have filled the Jinufes , but to have been
thruft out of them by the coarfe green injecti¬
on afterwards thrown into the veins.—
fmaii arteries which were obferved every
where opening upon the internal membrane
of the womb \—ff, others which feem to
have been torn in feparating the placenta .—
, And
PHYSICAL and LITERARY, 435
And, in all that part of the womb to which
the placenta had been fixed, when the cellu¬
lar membranes and extremities of the veins
were differed off ; innumerable arteries, of
all fizes, from that of a crow-quill down¬
wards, convoluted in a moft furprifing man¬
ner, were obferved; which were nothing
fo confpicuous in any other part of the womb,
treated in the fame manner.
Art,
43 6 ESSAYS and OBSERVATION^
A R T. XIX,
Of the Difference between Refpiration and the
Motion of the Heart., in fleeping and wa -
king Perjons, by Robert Whytt, M. IX
&c.
I /
OF all the parts of the human body, there
is none whofe ftrudture is more fub-
tile, and whofe feveral functions and ufes are
lefs known, than thofe of the brain . It is
little to be wondered at, therefore, if au¬
thors have failed of giving a fatisfa&ory ac¬
count of Jleep , which is one particular date
of this unknown organ,— We have elfe where
offered our conjectures concerning the reafon
why the vital motions continue in time of
Deep ; when the organs of fenfe become lefs
. fit to receive the impreffions of external ob¬
jects ; and when the mufcles of voluntary
motion are more relaxed and remain at reft 'h
But, as refpiration and the motion of the
hearty
* EfFay on the Vital and other Involuntary motions of a*
nimals, fedt. xii.
PHYSICAL and LITERARY.
437
heart, fuffer fome change in time of deep,
/. e. become then flower, fuller and more e-
quable, than when we are awake it may
be worth while to enquire a little into the
reafon of this phaenomenon .
It has been fhewn, that as the dilatation
of the ventricles of the heart, is owing to
the force of the refluent venous blood > fo
their contradtion is produced, by the fame
blood adting upon them as a Jlimulus and
that the heart can only be affedted by Jlimuli ,
in fo far as it is a fentient organ, i. e . en¬
dued with feeling J. Whence it muft follow,
that the flownefs of the pulfe in fleep, and
indeed in every other cafe, can only arife
from one or more of the following general
caufes. viz. i. A diminution of the ftimu-
lating quality of the blood. 2. Its flower re¬
turn to the heart; or, 3. A lefs degree of
fenflbility or aptitude for motion in the heart
itfelfo
* Boerhaave Inftitut. Med. § 599.
•f Vid. Effay on Vital and other Involuntary motions of
animals, left. iii. and iv.
J Ibid, fe&. x. p. 271. &e.
43S ESSAYS and OBSERVATIONS
»
L When one has eat or drunk a great deal
before deep, his pulfe will be, not flow, but
quick and fulls becaufe the ftimulating power
of the blood is increafed, by a large quantity
of chyle received into it. Much the fame
thing may happen from fleeping in too hot
an air, or under too great a weight of cloaths:
for we know, that heat quickens the circu¬
lation of the fluids in all animals. On
the other hand, when one has failed long
before fleep, and lies very cool, his pulfe
will, in time of it, be unufually flow.
But when the blood is neither loaded
with new chyle, nor altogether deftitute of
it ; neither too much heated by cloaths or
the external air, nor too cool, thro' want of
proper covering s its ftimulating quality will
neither be augmented nor diminifhed by
fleep ; but will continue the fame as in a per-
fon who is awake in the fame circumftances*
It remains therefore, that the flownefs of the
heart’s motion in time of fleep, be owing,
either to the flower return of the venous
blood to it, or to fome diminution of its fen-
Ability.
II. Every one knows, that the affections
of the mind difturb the motion of the hearty
that
PHYSICAL and LITERARY.
that the pulfe is quicker when we fit or ftand
than when we lye ; and that the a&ion of
the mufcles of voluntary motion, not only
promotes the return of the blood to the
heart, but determines it thither, with much
greater force than ufual. In fleep therefore,
where the horizontal pofture of the body,
the quiefcence of the voluntary mufcles, and
compofure of the mind, all concur to render
the return of the venous blood to the heart,
more equable and flow, the contraction of
this mufcle muft be renewed at greater inter¬
vals, and with more regularity, than when
we are awake, and the circulation is quicken¬
ed or difturbed by fome, or all, of the above-
mentioned caufes. But, if no farther cir-
cumflance, tending to retard the heart’s mo¬
tion, were found in deep, the pulfe flhould
be equally flow and full in a waking perfon
lying at red in a horizontal pofture, and
whofe mind is compofed, as in the fame per¬
fon in time of fleep ; which, however, does
not feem to be entirely the cafe : for tho’ the
difference may be fmall, and there may be
many caufes which may render it difficult, by
obfervation, to determine that difference with
any degree of certainty ; yet the remarkable
flowncfs
440 ESSAYS and OBSERVATIONS
fiownefs and fulnefs of the pulfe in the deep
fleep, accompanying an apoplexy or occafioned
by opium , makes it highly probable, that even
in the much gentler fleep of perfons in
health, the pulfe is fomewhat flower and
fuller, than it would be, merely from the
compofure of mind, horizontal pofition of
the body, and quiefcence of the mufcles of
voluntary motion. Let us therefore fee, whe¬
ther the flown efs and fulnefs of the heart’s
motion in time of fleep, may not be in part
owing, to fome diminution of the fenfibility
of this organ.
3. In time of fleep, as the exercife of the
feveral fenfes, is either fufpended or much
impaired 1 fo the fenfibility or feeling, with
which the organs of the body are more or
3efs endued, feems to be rendered lefs acute.
Thus we feel ourfelves affeded with a kind
of Jiupor , when we are juft falling afleep,
and are then infenfible of lefler Jiimuli . The
thin rheum, which, by irritating the wind¬
pipe, keeps us almoft perpetually coughing
when awake, gives us little or no difturbance
m fleep : any extraordinary Jlimulus in the guts
is alfo lefs perceived then ; and hence it is,
that 4 dofe of any purgative taken at night, is
piuch
PHYSICAL and LITERARY. 441
. much longer before it operates, than when it
is fwallowed in the morning. If the heart
therefore, like the other organs of the body,
becomes lefs fenfible or irritable in time of
fleep, it will not be fo quickly excited into
contraction as ufual,by the venous blood rufh-
ing into its cavities ; and hence its contracti¬
ons will not only be more flowly repeated,
but the pulfe will be full, becaufe the ventri¬
cles do not contradt, till they are much dis¬
tended with blood. This will thill further
appear, if wre confider how remarkably flow
and full the pulle is, in an apoplexy, where
the fenlibility of all the parts and their apti¬
tude for motion, are much more impaired
than in common fleep: and how opium , which
occafions fleep, and leflens the fenfe of feel¬
ing every where thro’ the body, when given
in a large dofe, renders the pulfe uncom¬
monly flow and full. Thus the heart of a
frog, into whofe ftomach and guts I had, an
hour before, injeCted a folution of opium ,
was obferved to beat near four times flower
than ufual ; and the auricle and great veins
leading to the heart, were remarkably dif-
tended with blood, as was alfo the ventricle
of the heart before every contraction. At
K k k the
ESSAYS and OBSERVATIONS
44^
the fame time the other mufcles of this ani¬
mal were fo intirely deprived of feeling as
not to be, in any degree, affeded by prick¬
ing or tearing their fibres 'h
Does not the flower digeftion of the ali¬
ment in time of fleep, proceed, partly, from
the periftakic motion of the ftomach and guts
being then repeated after longer intervals?
In dogs who have got a large dofe of opium , this
motion is very much !effenedor totally fufpend-
ed, the food laft received into the ftomach re¬
mains there indigefted, the guts are more
than ufualy empty, and the ladeal veffels in-
vifible*f\ In fieep, therefore, not only the
heart but the ftomach and guts alfo, become
lefts fenfible of the Jlimuhs ufually affeding
them, and confequently repeat their contra-
dions more flowly.
De Gorier , differing from Boerhaave and o-
ther authors, thinks, that the pulfe muft be,
not fuller, but fofter in time of fleep, becaufe
the circulation of the blood is allowed, then,
to proceed more (lowly than when we are a-
wake.
* Eflay on the Vital and Involuntary motions, &c. p. 372*
4 Kauu iropet, faciens Hippocrat, di&um, No 434.
PHYSICAL and LITERARY. 443
wake-f'. But, from what has been Paid, it ap¬
pears, that thefulnefsof the pulfe in fleep, is not
owing to the quicker circulation of the blood,
but to a lefs degree of fenfibility in the heart,
whereby its ventricles are not excited into
contraction, till they have been more fully
dilated, then ufual, by the returning blood.
It is, however, to be obferved, that the fui-
nefs of the pulfe in fleep, may be owing
partly, to the fluids paffing, with greater diffi¬
culty, thro’ the very fmall lateral arteries, and
the fecretory tubes of the glands^. For we
know that the fulnefs or foftnefs of the pulfe
does not depend, folely, upon the quantity of
blood thrown out by the left ventricle of the
heart, but alfo upon the more or lefs difficult
paflfage of this fluid thro’ the extreme arteries ;
fince, in proportion as thefe are obftruCled
or open, a greater or lefs refiftance will be
oppofed to the blood projected by the heart.
After what has been faid of the flownefs
of the heart’s motion in fleep, it will be eafy
to fhew why refpiration fhould be performed,
then, at greater intervals.
* Boerhaave Inftitut. med. § 597.
$ Exercit. de fomno et vigilia, § xl.
The
444 ESSAYS and OBSERVATIONS
The caufe exciting the alternate contracti¬
on of the infpiratory mufcles, is an uneafy
fenfation in the lungs, occafioned by the
blood pudied into their veffels by the right
ventricle of the heart If then lefs blood
is fent, in a given time, into the lungs, in
deep, than when we are awake 5 the neceffity
of new fupplies of freih air will be leffened,
and confequently infpiratron will be perform¬
ed at greater intervals.
Further, as in time of deep, the fenfi-
bility of the lungs, like that of the heart
and guts, mud be fomewhat impaired, re-
fpiration mud alfo, on this account, be per¬
formed more dowly 3 for the infpiratory
mufcles will not be excited into aCtion till a
greater degree of irritation, than ufual, be
occafioned by the blood accumulated in the
pulmonary vellels. And, to this it is owing,
that reipiration is not only dower but fome¬
what deeper in time of deep, than in a waking
perfon at red in a horrizontal politico.
In ccmatous and apopledic cafes, where
all the feelings of the body are much more
impaired than in ordinary deep, refpiration is
not only much dower and deeper than ufual,
but,
* EiTay on Vital and Involuntary motions,, &<p. p. 176. &:c*
PHYSICAL and LITERARY. 445
but, fometimes, after expiration is finished,
a paufe of 15, 20, 30, or more feconds will
intervene, before a new infpiration is begun.
Much the fame thing happens to animals
who have fwallowed too great a quantity of
opium
Now, if it be reafonable to afcribe the flow,
deep and interrupted breathing, in fuch
cafes, to the infeniibility which attends thofe
difeafes of the head ; and which opium never
fails to produce, when taken too liberally ;
are we not hence led to conclude, the lefs re¬
markable change of breathing which hap¬
pens in fleep, to be owing, partly, to the
fenfe of feeling in the lungs, being then
fomewhat diminilhed, tho’ in a much lefs
degree than in thofe morbid cafes?
To conclude with fum ruing up what has
been faid in a few words ; in ordinary fleep
the fenfibility of the heart and lungs fuffer
fo fmall a diminution, that their motions
will be very little more affedted by it, than
they would be from the horrizontal pofition
and reft of the body, and compofure of mind
attending it. In the deeper fleep, which
fucceeds great fatigue, the motions of the
heart
f EiTa y on the Vital and Involuntary motions, &c, p. 194.
44 6 ESSAYS and OBSERVATIONS
heart and lungs will be more obfervably al¬
tered. And, in the moft profound fleep, oc¬
casioned by opium or a morbid Rate of the
brain, where a general infenfibility reigns
over the whole body 3 the pulfe will become
much more remarkably flow and full, and
refpiration flower and deeper.
Art,
j
PHYSICAL and LITERARY, 447
A R T, XX,
Remarks on the IntercoJIal Mufcles , by Alex-
ander Monro, F. R. S. Profefor of
Anatomy in the Univerfty of Edinburgh.
TAUVR T*, fhewed the mifapplication
of ivlr. Bayle s propofed demon ftration
of the adtion of the internal intercoftal muf¬
cles, from his inattention to the ribs not
keeping in the fame parallelifm when they
are raifed, as when they are depreffed, becaufe
of the greater motion of the lower than of
the higher ribs ; and he took notice of the
fame demonitration, proving equally that
tne anterior part or thefe internal intercoftals
mint a 6t in inipiration, as Bayle would have
their pofterior part to a dt in expiration : but
neither he, nor any other writer of my ac¬
quaintance, has applied this demonftration
of Bayle s, which, granting the parallelifm
of the ribs to remain the fame, is a good
one, to account for the defedt of the inter¬
nal
* AxaU raifonn, part, z, chap. 14,
448 ESSAYS and OBSERVATIONS
nal intercoftals between the fpine and the an¬
gle of the ribs, and for the deficiency of the
external intercoftals from where the ribs be¬
gin to turn upwards to the Jlernum 5 a fadt
which anatomifts are now all agreed in.
The application of the demonftration to this
purpofe, is the intention of this paper*
Let AB {Jig. 1. Tab. viib) be the fpine,
CD the jlernum , EFGH, and IKLM two
ribs ; then EK and GM are lines in the di~
redtion of the external intercoftal mufcles,
and FI, and HL are in the direction of the
internal intercoftals.— — Now, fays Bayle3
If both ribs rife, the angle FEI muft be in-
larged, and its hypoteneufe FI, the fibres of
the internal intercoftal, muft be longer:
whereas mufcles generally are fhortened when
they adh — Near to the fpine, where the ribs
cannot be brought nearer at one time than
another, this reafoning is juft 5 and there¬
fore the internal intercoftals are not placed
nearer to the fpine than where the motion of
the ribs is large enough to allow the lower
rib to approach fo much to the one a-
bove it as to do more than compenfate for the
elongation of the hypoteneufe of the angle
FEI, /. e . the internal intercoftal is only to be
found
PHYSICAL and LITERARY. 449
found farther foreward than the angles of the
ribs.
Near to the Jlernum , the cartilages can¬
not be brought nearer ; and therefore, when
they are raifed up, HL, the fibres of the
internal intercoftal may be (hortened, becaufe
the angle HML is made lefs : but, if there
were fibres of the external intercoftal here,
as GM, they would be made longer, becaufe
the angle GHM is enlarged by railing the
ribs ; and therefore no external intercoftal
mufcles are placed at this forepart of the tho¬
rax .
L 1 1
A R T.
45°
ESSAYS and OBSERVATIONS
Art. XXL
The Cure of a fraSiured Tendo Achillis ; by
the fame.
OU R predeceffors were either not fub-
jed to the breaking or tearing the ten-
do Achillis , or it was miftaken for a fprain, or
fome fuch other difeafe by phyficians and fur-
geons ; for it is rarely taken notice of in
books ; and the oldeft and heft pradifers
here aftiire me, they had not obferved it or
heard of it, till between twenty and thirty
years ago ; fince which this accident has
happened to a confiderable number of peo¬
ple of this country, of whom I know fix-
teen, and fever al of thofe have broke the
tendons of both legs ; among the reft, I have
been a fufferer this way; and, upon a compa¬
nion with my brethren in afflidion, my cure
is the moft compleat of any I know ; there
being neither pain,, ftiffnefs, weaknefs nor
obfervable fhriveling in my left leg where the
tendo Achillis was broken : whereas moft of
the other gentlemen have fome of thofe un-
eafineffes.
PHYSICAL and LITERARY. 451
eafinefles, and feveral have all of them. On
this account, I think it my duty, for the be¬
nefit of future patients, to make my method
of management as public as I can ; which
probably will be beft done, by communica¬
ting it to your fociety.
When my tendon was torn, it cracked as
loud as if I had fuddenly broke a nut under
my heel 5 which the company believed had
happened : and I had fuch a feniation as
made me imagine that the heel of my fhoe
had ftruck a hole in the floor ; which is the
feeling that feveral have had as well as I :
while others complain as if they had recei¬
ved a fmart ftroke with a ftone or cane on the
part. — I fufpe&ed immediately what the
cafe was ; and therefore, after feeling where
the hollow was, between the ends of the
broken tendon, I took the left foot in my
right hand, with which I extended the foot
ftrongly ; and, as foon as I was put in a feat,
preffed down the calf of my leg with my o-
ther hand : in which poflure I kept them
till Meff. John Douglas and James Rujjel fur-
geons of this place came ; and, after being
fatisfied of the rupture, by prefling their
fingers into the hollow between the two ends
of
ESSAYS and OBSERVATIONS
452
the tendon, they applied compreffes, and a
bended board on the upper part of my foot
and fore part of my leg, which they kept, as
near as they could, in a flraight line, by a
tight bandage made with a long roller.— This
dreffing became foon too uneafy for me to
bear, and the board was liable to fhuffie
whatever care was taken in the application
of the bandage : therefore I changed it for
the following compound one, confiding of
two pieces. (See Tab. viii.)
Fig, 2. is a foot-fock or flipper A, of
double quilted liking ; from the heel of
which B, the quilted ftrap C, is of fuch a
length as to come up above the calf.
Fig. 3. A ftrong quilted calf-piece L, with
pye-holes MM on each fide, through which
a lace, Jig. 4. is to be pafled 3 and, with a
buckle N, fo placed on its back-part, that,
when the lacing was on the outfide of the
leg, the buckle was in the middle of the
lower part. Two rows of pyehoies are here
reprefen ted on one fide, either of which is
to be ufed according; to the thicknefs of the
o .
w o
t *
Having
/
PHYSIC AL and LITERARY. 453
Having then wrapped foft flannel, fmoak-
ed with the fumes of benzoin, round my foot
and leg 5 I put on, as in fig. 5. the foot-fock
A, and calf-piece L, and bringing the ftrap C,
thro' the buckle N, I could by it extend
the foot, and pull down the calf to what de¬
gree I thought fit, and there fecure it with
the buckle.
This bandage anfwering my intention quite
well, I wore it night and day, drawing the
ftrap tighter when I inclined to deep, and re¬
laxing it when I was fully awake and on my
guard ; at which time, likeways, I placed
my foot on a ftool, in the pofture reprefent-
ed at S, and frequently fhifted the calf-piece
or made the lacing of it loofer, to prevent
the dwelling of my foot, whichit was in dan¬
ger of occafioning, when it became too tight,
by being drawn down by the ftrap.— After a
day or two, I found my toes uneafy, from
the foot-fock preftmg them ; and therefore
I undid the fowing of it at the toes, from d \
tod-, and have caufed it always fince to be
made open there, for others who ufed it.
During two weeks, I made no motion
nor effort with my foot 3 but was carried
on a chair, running on carters, from one part
of
454 ESSAYS and OBSERVATIONS
of my houfe to another. After this, I began
to move the foot backwards and forewards
fo gently as not to give pain, and gradually
increafed thofe motions 3 but always flopped
the flexion of the foot, or extenfion of the
leg whenever 1 felt the lead: uneafinefs : fre¬
quently I continued thefe motions for half
an hour together, with the difeafed limb 3 but
kept the other as much at reft as I could.
When I began to walk, I always put the
left leg fome way before the right, that the
left foot might be well extended; making ufe
of a cane in my right hand, to prevent any
danger of falling.
The void between the two ends of the di¬
vided tendon, became infenfible in few days,
except that a foftnefs was felt there, more
than any where elfe ; but this part turned
gradually thicker and harder, till a knot was
formed in it, which one, in feeling thro’ the
teguments, would have thought to be a piece
of cartilage, as large as a middle fized plumb,
which has greatly decreafed, and become
Softer, for fome years pa ft 3 fo that, at pre¬
fect, it is much lefs perceptible than for¬
merly.
Some
PHYSICAL and LITERARY.
455
Some weeks after the accident, I began to
pour cold water on my leg and foot, caufing
them to be well rubbed immediately after ;
but the water, inftead of flrengthening the
member, as I expedted it would have done,
made it cold and weak ; for which reafon I
foon forebore the ufe of it, and caufed the
leg to be rubbed twice a-day ftrongly, with
unguent um altheae , or fome fuch greefy fluff,
to protect the fkin from excoriation by the
fridtion. This manoeuvre was continued till I
began to employ the limb freely.
Being obliged to go abroad after fix weeks,
I put on a pair of fhoes with heels about two
inches high, and applied the machine, which
I am juft now to defcribe, in the day time,
inftead of the former bandage; which, how¬
ever, was always put on at night, for a month
more.
The new machine, fig . 6. was a piece of
fteel, the middle ftalk of which A, is nar¬
row but ftrong : the ends BB, are then broad
and concave, adapted to the convexity of the
foot and forepart of the leg. Three ftapples
CCC, ftand up from the forepart of the fteel,
one being in the middle of each of the broad
ends, and the third in the middle of the
ftalk*
45 6 ESSAYS and OBSERVATIONS
ftalk. All the Reel except the ftapples was
covered with chammoy leather, and the con¬
cavities of BB, wrere well buffed, as the foft-
er rupture bands commonly are.
After 1 had put on my fhoes and {lock¬
ings, one end of this machine was put on
the broad of my foot, nearer the toes than
the buckle of the fhoe ; and the other end
was placed on the fore part of the leg : then
one ribband, or a thong of leather, fig . 7, 8,
was put round the foot, and another round
the leg, to pafs thro' the twTo ftapples near
the ends of the machine, and there fecured
with ftraps or buckles, but without being
drawn tight,— A third ftrap or ribband, fig.
9. having its middle D, applied in the hollow
of the foot, immediately before the heel had
its ends pafied on each fide of the foot, thro5
a firms or noofe EE, of a fourth thong of
leather F, that came round the quarter-heel
of the fhoe, to be afterwards put thro’ the
middle dapple \ where, after thefe ends GG
were drawn as tight as was thought conveni¬
ent for extending the foot, they were fecured ’
with the buckle, or with knots. See the ap- .
plication in fig . 10.— I wore this machine al¬
ways in the day time, for five months : tho*.
as
sBggBi -fl5fe>
im^t IjjL:
/
w
I
FHYSICAL and LITERARY. 457
as it is inconvenient, by fhuffiing out of its
place fometimes ; I think a thong of leather
fowed at one end to the upper middle part of
the quarter-heel of the fhoe, and fattened at
the other end to a garter, put above the
calf of the leg, would ferve inftead of it
without inconvenience.' - - -All that time
I never walked the ftreets, but was carried in
a chair.- — -In going down ftairs, I al¬
ways put the difeafed leg firft down at each
ftep 5 and, in coming up, I put the found
leg foremoft, by which I ffiunned the ftretch-
ing and retearing of the new louldered Anew,
which, I knew from what others had fuffered,
might have made the cafe worfe than it was at
firft. — The habit I had got of walking after
this manner in ftairs, became fo much a fe-
cond nature, that I had afterwards difficulty to
learn to go up and down in the ordinary way,
with the feet alternately.
I continued the high-heeled fhoes for two
years, caufing my boots to be made after the
fame fafhion, when I began to ride ; but
have gradually fince retrenched their height,
till now I wear them of the common make0
During all that time too, I mounted my
horfe at the right fide inftead of the left one,
M m m th-M
458 ESSAYS and OBSERVATIONS
that I might fhun the rearing my whole
weight, by the force of the weakened gaflro-
cnemei mufcles ; and to prevent the accident
of ftraining them, in cafe the horfe Rumbled,
I kept the left foot deep in the ftirrup. In
walking up hill, I put that foot a-crofs; and,
in fhort, guarded againft every other ftretch-
ing ftep or motion.
On comparing the lize of the calfs of the
two legs at prefent, the left one is a little
fmaller than the right one, efpecially in the
morning ; but fo little, that it is fcarce per¬
ceptible : thro’ the day, the difference be¬
comes lefs. — -The tendo Achillis that was bro¬
ken, is, as mo ft other tendons cured after
breaking, confiderably thicker and harder
than the other ; but one muft be told it is fo7
before he can dilcover it by the eye.
A R To
PHYSICAL and LITERARY. 459
Art. XXIL
An Account of the Dijeafe called Mill-Reek by
the Miners at Leadhills, in a Letter Jrom
Mr. James Wilson, Surgeon ^Durrif-
deer, to Alexander Monro, P. A.
IN obedience to your defire, I fend what I
haveobferved concerning the difeafe, which
the people at Leadhills call the mill-reek , and
which all the inhabitants there are fubjedt to ;
but it moftly feizes, and violently affedts the
men whofe daily bufinefs it is to melt down
the lead. The melting-houfes, where this is
done, are called mills ; becaufe the bellows
there are worked by water-mills.
In the {lighter fliage of this difeafe, an un-
eafinefs and weight is found about the {lo¬
rn ach, efpecially near the cartilago enfij or mis ;
and fometimes it appears like a colic in the
inteftines. The fpittle of the fick is fweet,
and fomething of a blueifh colour, refem-
bling what one obferves when he chews lead,
v— The pulfe is a little low; the {kin is all over
cold
460 ESSAYS and OBSERVATIONS
cold ; and a clammy fweat frequently breaks
out, — The legs become feeble with a prick¬
ling numnefs ; and there is a debility and
lazinefs in all the body.- — The appetite goes
away, and they don’t digeffc what food they
take,— Sometimes a diarrhea makes a cure ;
but, if it continues too long, it is very hurt¬
ful, — -In this fiadium the fick are yet able to
p* o about and to work.
o
Jbux, if thefe fymptoms continue long,
and fpirituous liquors are drunk with an em¬
pty ftomach, or after working lead ; the di-
feafe comes to its fecond ftage : in which,
to the former complaints, are added a fixed
pain in the ftomach and guts, efpeciaily in
the lower part of the abdomen, extending
itfelf from the one os ilium to the other.—
The patients become very coftive, with the
fenfe of fomewhat gnawing their inteftines ;
and the pulfe turns quick with heat on the
fkin.— Giddinefs, with vehement pain, feizes
the head 5 which is fucceeded by an infenfi-
bility and delirium , like madnefs of the worft
kind 5 in fo much that they tear their own
fiefh, and bite their hands $ the extremities
tremble, and are CQnyulfed ; at laft they fall
low.
PHYSICAL and LITERARY. 461
low, the pulfe intermits at every 3d or 4th
ftroak, and they die in a coma or apoplexy.
The reek or fmoak rifing from the melting
lead, is believed to be the caufe of this di-
feafe ; becaufe the melters, who are mod
ex pc fed to the fmoak which comes out often
full in their faces, are mod fubjedt to this
difeafe, the mill-reek.— The people here fay
they have feen birds, in a cairn moift day,
attempting to fly thro' the fmoak of fuch a
chimney, fall down dead.— Cattle, which
pafture near to mills, are often killed $ and
therefore fhepherds take great care to keep
their fheep at a diftance ; which, if not by
the fmoak, muft be hurt by the grafs, which
J often fee made blue by the fmoak falling
on it. And other animals differ from the
water impregnated with the fumes, or with
the lead wafhed in it.
The fymptoms in them are very like to
what men differ. Dogs, in the laft ffage, lie
either dull and ftupid, or bite and fnatch ate-
very creature that comes near them ; nay, they
will gnaw and tear up the ground on which
they lie, after- they cannot raife thenifelves
pn their lees,
Tm
46 2 ESSAYS AND OBSERVATIONS
The people at Leadhills are fo averfe to o-
pening of dead bodies, that I could never
prevail upon them to allow me to open any
who died of this difeafe. But, in a dog
who had it, I found jludge * lying on the in¬
ner coat of the ftomach and inteftines j and,
in feveral parts, it was turned to a cruft.—
The guts were much in flammed in fome
places, and in others a mortification was begun
with holes thro* them. —His faeces were very
hard ; and, where they were of little quan¬
tity, the coats of the guts were thick, and
the paffage thro* them lefs.
If proper medicines are given in the firft
ftage of this difeafe, the patient generally
recovers.— If it goes on till giddinefs begins,
the fuccefs is doubtful ; and when the cure
is delayed to be attempted a little longer, the
difeafe almoft conftantiy proves mortal.
If the work-people at Leadhills would ufe
the following precautions, they might fave
themfeives from this difeafe, at lea ft would
have it very mild.
I. No man ought to go to work falling ; and
he ought to take oily or fat food : the Englijh
mill-
* The fine particles of lead which fubfide flowly in water*
in which lead has been walhed.
PHYSICAL and LITERARY. 463
mill-men on this account hold much better
out than our countrymen. A glafs of fweet
oil pure, or mixed with a little aqua vitae ^
would be a good morning draught.
II. Physic fhould be taken Spring and
Harveft, and whenever any effedts of the reek
are felt.
III. Ardent fpirits ought to be drunk ve¬
ry fparingly ; and ought never to be taken in
time of work at the mill, or immediately af¬
ter it. They increafe and fix the bad effects
of the leady fmoak.
IV. No mill-man, when heated by work,
ought to go into cold air ; but to put on his
cloaths immediately, and return to his lod¬
ging, to change his working cloaths for o-
thers, and cool gradually: by which he would
prevent catching cold. In this article they
are very carelefs.
V. Immediately after coming from
work, the aliment fhould be moftly liquid^
as broths.
VI. Low and poor diet makes them more
liable to be affected, and lefs able to under¬
go a cure : thefe workmen ought to feed on
good meat.
VII,
464 ESSAYS and OBSERVATIONS
VIL When their bufinefs can allow, they
fhouid go out of the reach of the reek, • to
breathe an untainted air, and to take victuals
free from lead. But I mu ft caution the la¬
bourers at Leadhills not to take long journeys :
they are more hurt by travelling one day than
by working two.
The cure of this difeafe depends principal¬
ly on cleaning the primce vice: and therefore,
after blooding fuch patients, if they are ple¬
thoric, I give them a vomit of emetic wine or
tartar 3 which muft be a dole double to what
would vomit another perfon \ otherways it
would have no effedt, efpecially when the
difeafe is violent or has continued long. My
father, who has had long practice with fuch
patients under the mill-reek, has always fine¬
ly powdered vitrum antimonii ready > of which
he gives half a drachm for a dore 5 and du¬
ring its operation, warm water is to be drunk
plentifully. If the vomit operates well, and
purges brifkly too, the patient is in a fair way
of recovering ; which a fecond, but a milder
dofe of ipecacuanna with feme tartar emetic
mixed, often makes compleat: but, if the
emetic neither vomits nor purges, the patient
is generally Worfe for it> and a ftronger dofe
fli 0 uld
PHYSICAL and LITERARY. 4 65
fhould be given foon.— If it vomits but does
not purge; a cathartic of the antimonial kind,
or of jallap and mercury, in greater than or¬
dinary quantities, ought to be given : and
during the time of purging by the emetic or4
cathartic medicine, the patient ought to drink
Warm broth plentifully. —The vomits and
purgatives ought to be repeated at proper in¬
tervals, till the uneahnefs in the domach and
guts, from the difeafe, is gone.— If thefe me¬
dicines over-do, an opiate may be given at
night ; but this is to be adminiftred fparing-
ly, lead it bring or increafe codivenefs, which
is the word thing can befal the patient. At
the fame time, emollient, anodyne, and lax¬
ative clyflers, are frequently to be injected
for emptying the guts, if the purgatives do
not their duty.
When blood or matter are paffed with the
faeces , the emetics and purgatives are to be
abdained from, till, by healing, baifamic,
but laxative clyfters, and mild food, this ap¬
pearance ceafes.
When the belly is much fwelled, emol¬
lient fomentations fhould be often applied to
it 5 but, if the madnefs is begun, little elfe
can be done, than to endeavour to keep the
N n n patent
466 ESSAYS and OBSERVATIONS
patient quiet during the little time he has to
live.
Sometimes it happens, that, after the com¬
plaints of ftomach and guts are gone, a prick¬
ling pain and feeblenefs remain in the legs*,
much like to a rheumatifm ; for which, fri¬
ction, with a coarfe cloath or flefh-brufh, is
neceflary. If that fails, ung. nervinum with
oh terebinth . mixed, is to be rubbed on every
night, before the fires after which, the mem¬
ber is to be wrapped in flannel.— If thefe
pains are violent, or the feeblenefs relembles
palfy; bidders ought to be applied to the fkin
under which the large nerves are fituated,
and the medicines proper in a palfy are to be
given.
Some are fo wafted before the cure is corn-
pleated, that they remain afterwards emacia¬
ted, weak, and as if they were hedfic, with a
giddinefs in their head : and fometimes they
chat to no purpofe, or feem hypochondriac.
In this condition, the patient fhould go to
the country, to ride a-horfe-back fome miles
every day ; and, at the fame time, fhould take
bitters with bark and fteel. If the giddinefs
continues, I have given with fuccefs, pilul.
de myrrh . with a fmall proportion of camphor *
'End of the firji Volume »
INDEX.
A.
A&ion and re-a&ion in matter, pag. 33. and 134.
Adive being (what) 86.
Aether (Newtonian) not the caufe of gravity, 49.
Alutn, contained in the Hartfell $paw\ 351, and 357. &c.
Al st on (Dr. Charles) his differtation on the fexes of
plants, 205.
Anajiomofis (none betwixt the uterine and fecundary veffels
419.
Attraction and repulfion, not owing to any aCtive power in,
bodies, 1 2 1 .
Aurora Borealis , the matter of it, the fame with lightening
and electricity, 195.
B.
Baxter (Mr.) an error of his, with regard to the Inertia
of matter, n8.
Bodies, indifferent to reff or motion, 108.
C.
Caufes, the abfurdity of ah infinite feries of them, 130^
Circle, fome properties of it demonllrated, 147.
Conic fedions (fome properties of them) 1 70.
Confumption of the lungs cured by Hartfell Spaw9 364.
D.
Deity, his continued concurrence, no argument againll the
perfection of the world, 133.
Penniston (Mr. George) his account of a cure perform¬
ed by an alterative mercurial medicine, 390.
E.
INDEX.
E.
Ecliptic, the caufe of the variation of its obliquity, 173,
Fle&ricity, obfervations on it, 189,
Epidydimis , compofed of a fingle tube, 401.
F.
Farina of plants, conje&ures concerning its ufe, 279.
Foetus, its fituation in the womb, 422.
Force of a body in motion, proportionable to its velocity,
64.
Forces of bodies in motion, 90. &c.
Fra&ure of the 'Tendo Acbillis , its cure, 450.
Gs
Gravity (of) 42.
. - a power inherent in matter, 52.
— - -the refemblance betwixt it and magnetifm, 11 1.
~ - —owing to the continued and regular operation of an
intelligent caufe upon matter, 1 15.
- .—/Theorems concerning the laws thereof towards Jufim
ter , 188.
Gray (James) of the meafures of Scotland, compared with
thofe of England, 20.0 .
Grew (Dr. Nehemiah) the fir# who taught that female
plants were impregnated by the Jarina of the male, 213.
H.
Fd art fell Spanjj, Experiments and obfervations upon it, 341.
~ — - ftrongeft in a wet feafon, and weakeif in a
dry one, 354.
- - - — — - what difeafes cured by it, 363, and 364.
- Directions how to ufe it, 365.
Heart, its motion flower in fleep, and why, 437.
Home (the Honourable Henry) on the laws of motion, 1.
Horseburgh (Dr. William) his experiments and obferva°
dons on the Hcirtfell Spa<w, 341.
I
1 N D E
X
i.
Immateriality, the meaning of it, 124.
Impulfe ^an analyfis of it) 30.
Inertia of bodies, remarks on it, 30.
Inertia of a body at reft, 75. &c.
Inertia of a body in motion, 79. &c.
Jupiter, changes obferved on his furface, 1 84,
L.
Lead, a remarkable difeafe produced by it, 459,
Lime-water, of its various ftrength, 372.
Linnaeus (Carolus) his arguments in favour of the fexes
of plants, 224. refuted, 232. &e.
Lining (Dr. John) on the anthelmintic virtues of the root of
the Indian-Pink , 386.
M.
MacLaurin (Colin) on the variation of the obliquity of
the ecliptic, 173.
— - - - ——on the fudden changes in the furface
of Jupiter , 184.
MacFait (Dr. EBENEZER)his obfervations on thunder anc|
electricity, 189.
- - -his account of fome phenomena
in foggy weather, 197.
Magnetifm, owing probably to fome effluvia, 1 1 1.
Matter, whether endued with a power of motion, 6„
• - — incapable of thinking, 122.
Maupertuis, a notion of his refuted, 129.
Meafures of Scotland and England compared, 201.
Menjlruum , (an univerfal one) by no means probable, 286.
Mill-reek , a difeafe common among thole who work in lead-
mines, its hiftory and cure, 459.
Monro (Alexander) his defcription of the feminal veftels,
396.
- - —his additional obfervations on gravid
Uteri , 426.
Monro
1
IN D E X.
Monro (Alexander, P. A.) his remarks on the intercofhl
mufdes, 447.
- - - - — — - — —on the cure of a fradlured Tendo A-
chillis, 450.
Monro (Dr. Donald) his remarks on gravid uteri, 403.
Morland (Samuel) his opinion concerning the impregna*
tion of plants, 216.
Motion, the laws of it, 1.
- - -feveral definitions of it, 3, and 4.
- a continued adtion, 18.
• — - the continuation of it, owing to a power in matter,
22.
— — the communication of it, 26.
the force of bodies in it, 61.
— remarks on the laws of it, 1 , and 70-
- - - not adtion, but the effedt of adtion, 85*
■ . the communication of it, 83, 88.
- - a body in it will continue fo for ever, 106*
"——of its continuation, 108.
— ■ — a power of beginning it, infers a power of thinking,
1 14.
Mufdes (intercoflals) remarks on them, 447.
N.
Newton (Sir Isaac) does not afcribe adtivity to matter*
13°,
P.
PajPpi (Alexandrini) fropofitio generation fatta, 141.
Pink ( Indian J its root a good remedy againfi: worms, 386.
Plants, of their fexes, 205.
— — -conjedtures about the ufe of their jarina or dull, 279.
Placenta , not always fixed to one particular part of the womb,
421*
Plummer (Dr Andrew) his remarks on chemical folutions,
and precipitations, 284.
- - - experiments on neutral laics,
POLENJ,
I N D E X*
Poleni, his experiment of balls falling upon foftclay, 90.
Polypus, the phenomena of it, confident with the indivift*
bility and unity of a thinking fubflance, 125.
Precipitations (chemical) remarks on them, 303.
Quick-fllver, injected into the epidydimis , 396.
R.
Rainbow, formed round one’s fhadow in the mill, 19$,
Re-adion, equal to adion, 104.
Refinance in matter, the effed of an adive power, 21.
- of a fubflance perfectly inadive, 72.
Refpiration, flower in time of fleep, and why, 444.
S.
Salts (neutral) experiments on them, 313.
Sinufes of the womb, a defcription of them, 430.
Solutions (chemical) remarks on them, 2S4, and 329.
Soap-leys, their component parts, 383.
Sleep, the difference it makes on refpiration and the motion
of the heart, 436.
Streamers, of the fame materials with lightening, 193,,
Stewart (Dr. John) his remarks on the laws of motion, 70 .
Stewart (Matthew) Pat pi Alexandria propojjtio genera-
lior fadla, 1 4 1 .
Subfiances, material and immaterial, what, ua
T.
Thinking, has no relation to matter, 123.
Theophrastus, his account of the fexes of plants, 20$, tfc*
Thunder, obfervations on it, 189.
U.
Uteri (gravid) remarks on them, 403, and 426,
Uterus , its figure when impregnated, 414,
Uteri (gravid) their thicknefs, 417.
V.
X.
I N D R
V.
Vis infita, or vis inertia, l6.
Vis infita and nris inertia or refijientia , different powers Ixi
matter, 23*
Vitriolum Mart is nativum, found in the Hartfell Spa<zv, 355.
Venereal lues, cured by large dofes of an alterative mercu¬
rial medicine, 390.
, ’ ; f
V/
Whytt (Dr. Robert) on the various ftrength of different
lime-waters, 372.
*= _ — — -his account of the difference between refpiration and
the motion of the heart, in deeping and waking perfons*
436.
Wti/SON (Mr. James) his account of the Mill-reek , 459.
ERRATA-
Page f 7 7. line 17. after thing , add that. p. 178. 1. 16. af.
that add which, p. 184. 1. 4. for in read on. p. 311. 1. 8*
for falls x.fall. p. 410. 1. ■penult, f. IF. r. V . p. 413. 1. 2 1.
f. ‘14. r. 4. p. 424. 1. 10. f. IF. and F. r. F. and VI. p.
455. 1. 22. f. then r. thin .
To the BOOKBINDER.
*
Place Tab. I. fronting Pag. 172.
— - — — II. - — 184.
- - — —III. — — . 400.
- - -IV. V. VI. VII.—— 414.
•— - -VIII. - - 4$.
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